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Moosa MS, Russomanno G, Dorfman JR, Gunter H, Patel C, Costello E, Carr D, Maartens G, Pirmohamed M, Goldring C, Cohen K. Analysis of serum microRNA-122 in a randomized controlled trial of N-acetylcysteine for treatment of antituberculosis drug-induced liver injury. Br J Clin Pharmacol 2023; 89:1844-1851. [PMID: 36639145 PMCID: PMC10952339 DOI: 10.1111/bcp.15661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/30/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023] Open
Abstract
AIM Serum microRNA-122 (miR-122) is a novel biomarker for drug-induced liver injury, with good sensitivity in the early diagnosis of paracetamol-induced liver injury. We describe miR-122 concentrations in participants with antituberculosis drug-induced liver injury (AT-DILI). We explored the relationship between miR-122 and alanine aminotransferase (ALT) concentrations and the effect of N-acetylcysteine (NAC) on miR-122 concentrations. METHODS We included participants from a randomized placebo-controlled trial of intravenous NAC in AT-DILI. ALT and miR-122 concentrations were quantified before and after infusion of NAC/placebo. We assessed correlations between ALT and miR-122 concentrations and described changes in ALT and miR-122 concentrations between sampling occasions. RESULTS We included 45 participants; mean age (± standard deviation) 38 (±10) years, 58% female and 91% HIV positive. The median (interquartile range) time between pre- and post-infusion biomarker specimens was 68 h (47-77 h). The median pre-infusion ALT and miR-122 concentrations were 420 U/L (238-580) and 0.58 pM (0.18-1.47), respectively. Pre-infusion ALT and miR-122 concentrations were correlated (Spearman's ρ = .54, P = .0001). Median fold-changes in ALT and miR-122 concentrations between sampling were 0.56 (0.43-0.69) and 0.75 (0.23-1.53), respectively, and were similar in the NAC and placebo groups (P = .40 and P = .68 respectively). CONCLUSIONS miR-122 concentrations in our participants with AT-DILI were considerably higher than previously reported in healthy volunteers and in patients on antituberculosis therapy without liver injury. We did not detect an effect of NAC on miR-122 concentrations. Further research is needed to determine the utility of miR-122 in the diagnosis and management of AT-DILI.
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Affiliation(s)
- Muhammed Shiraz Moosa
- New Somerset Hospital, Department of MedicineUniversity of Cape TownCape TownSouth Africa
| | - Giusy Russomanno
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Jeffrey R. Dorfman
- Division of Medical Virology, Department of PathologyUniversity of StellenboschCape TownSouth Africa
| | - Hannah Gunter
- Division of Clinical Pharmacology, Department of MedicineUniversity of Cape TownCape TownSouth Africa
| | - Chandni Patel
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Eithne Costello
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Dan Carr
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Gary Maartens
- Division of Clinical Pharmacology, Department of MedicineUniversity of Cape TownCape TownSouth Africa
| | - Munir Pirmohamed
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Christopher Goldring
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative BiologyUniversity of LiverpoolLiverpoolUK
| | - Karen Cohen
- Division of Clinical Pharmacology, Department of MedicineUniversity of Cape TownCape TownSouth Africa
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Olwagen CP, Izu A, Mutsaerts EAML, Jose L, Koen A, Downs SL, Van Der Merwe L, Laubscher M, Nana AJ, Moultrie A, Cutland CL, Dorfman JR, Madhi SA. Single priming and booster dose of ten-valent and 13-valent pneumococcal conjugate vaccines and Streptococcus pneumoniae colonisation in children in South Africa: a single-centre, open-label, randomised trial. Lancet Child Adolesc Health 2023; 7:326-335. [PMID: 36934731 PMCID: PMC10127219 DOI: 10.1016/s2352-4642(23)00025-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/25/2023] [Accepted: 01/25/2023] [Indexed: 03/17/2023]
Abstract
BACKGROUND Pneumococcal conjugate vaccine (PCV) immunisation has reduced vaccine-serotype colonisation and invasive pneumococcal disease in South Africa, providing the opportunity to consider transitioning from a two-dose (2 + 1) to one-dose (1 + 1) primary series and a booster dose. METHODS In this single-centre, open-label, randomised trial done in South Africa, infants aged 35-49 days without HIV infection, without childhood immunisations except for BCG and polio, and with gestation age at delivery of at least 37 weeks of age, a birthweight of at least 2500 g, and weight of at least 3500 g at the time of enrolment were randomly assigned (1:1:1:1:1:1), through block randomisation (block size of 30), to receive a single priming dose of ten-valent PCV (PCV10) or 13-valent PCV (PCV13) at either 6 weeks (6-week 1 + 1 group) or 14 weeks (14-week 1 + 1 group), compared with two priming doses at 6 weeks and 14 weeks (2 + 1 group), followed by a booster dose at 9 months of age in all groups. The primary objective of the trial has been published previously. We report the secondary objective of the effect of alternative doses of PCV10 and PCV13 on serotype-specific Streptococcus pneumoniae colonisation at 9 months, 15 months, and 18 months of age and a further exploratory analysis in which we assessed non-inferiority of serotype-specific serum IgG geometric mean concentrations 1 month after the booster (10 months of age) and the percentage of participants with serotype-specific IgG titre above the putative thresholds associated with a risk reduction of serotype-specific colonisation between the 1 + 1 and 2 + 1 groups for both vaccines. Non-inferiority was established if the lower limit of the 95% CI for the difference between the proportion of participants (1 + 1 group vs 2 + 1 group) above the putative thresholds was greater than or equal to -10%. All analyses were done in the modified intention-to-treat population, which included all participants who received PCV10 or PCV13 according to assigned randomisation group and for whom laboratory results were available. The trial is registered with ClinicalTrials.gov, NCT02943902. FINDINGS 1564 nasopharyngeal swabs were available for molecular serotyping from 600 infants who were enrolled (100 were randomly assigned to each of the six study groups) between Jan 9 and Sept 20, 2017. There was no significant difference in the prevalence of overall or non-vaccine serotype colonisation between all PCV13 or PCV10 groups. PCV13 serotype colonisation was lower at 15 months of age in the 14-week 1 + 1 group than in the 2 + 1 group (seven [8%] of 85 vs 17 [20%] of 87; odds ratio 0·61 [95% CI 0·38-0·97], p=0·037), but no difference was seen at 9 months (nine [11%] of 86 vs ten [11%] of 89; 0·92 [0·60-1·55], p=0·87) or 18 months (nine [11%] of 85 vs 11 [14%] of 87; 0·78 [0·45-1·22], p=0·61). Compared with the PCV13 2 + 1 group, both PCV13 1 + 1 groups did not meet the non-inferiority criteria for serotype-specific anti-capsular antibody concentrations above the putative thresholds purportedly associated with risk reduction for colonisation; however, the PCV10 14-week 1 + 1 group was non-inferior to the PCV10 2 + 1 group. INTERPRETATION The serotype-specific colonisation data reported in this study together with the primary immunogenicity endpoints of the control trial support transitioning to a reduced 1 + 1 schedule in South Africa. Ongoing monitoring of colonisation should, however, be undertaken immediately before and after transitioning to a PCV 1 + 1 schedule to serve as an early indicator of whether PCV 1 + 1 could lead to an increase in vaccine-serotype disease. FUNDING The Bill & Melinda Gates Foundation.
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Affiliation(s)
- Courtney P Olwagen
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Alane Izu
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Eleonora A M L Mutsaerts
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Pediatrics, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Lisa Jose
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Anthonet Koen
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Sarah L Downs
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Lara Van Der Merwe
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Matt Laubscher
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Amit J Nana
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Andrew Moultrie
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Clare L Cutland
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Faculty of Health Science, and African Leadership in Vaccinology Expertise, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeffrey R Dorfman
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Department of Medical Virology, Department of Pathology, Stellenbosch University, Cape Town, South Africa
| | - Shabir A Madhi
- South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Infectious Diseases and Oncology Research Institute, University of the Witwatersrand, Johannesburg, South Africa; Faculty of Health Science, and African Leadership in Vaccinology Expertise, University of the Witwatersrand, Johannesburg, South Africa.
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3
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Ramocha LM, Dorfman JR, Groome M, Baillie V, Verwey C, Laubscher M, Nunes MC, Madhi SA. Human Metapneumovirus-Associated Hospitalization in HIV-1 Exposed Uninfected and HIV-1 Uninfected Children Less Than 5 Years in South Africa. J Pediatric Infect Dis Soc 2023; 12:53-55. [PMID: 36306473 DOI: 10.1093/jpids/piac112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 10/27/2022] [Indexed: 11/15/2022]
Abstract
Using hospital surveillance data, we estimated Human metapneumovirus (hMPV) hospitalization incidence by age and HIV-exposure status. hMPV-associated hospitalization incidence was highest in <1-year children. Incidence rate ratios of HIV-exposed over unexposed children were 1.5 (95%CI 0.9-2.4) for <6-month children, 1.4 (95%CI 0.7-2.4) for 6- to 11-month children and 0.9 (95%CI 0.4-1.9) for 12- to 59-month children.
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Affiliation(s)
- Lesego M Ramocha
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa
| | - Jeffrey R Dorfman
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa.,Division of Medical Virology, Department of Pathology, Stellenbosch University, Cape Town, South Africa
| | - Michelle Groome
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa.,African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Vicky Baillie
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa
| | - Charl Verwey
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Pediatrics and Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Marius Laubscher
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa
| | - Marta C Nunes
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa
| | - Shabir A Madhi
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Sciences, Johannesburg, South Africa.,African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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4
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Ramocha LM, van den Hoogen BG, Baillie V, van Nieuwkoop S, Cutland CL, Jones S, Moultrie A, Izu A, Verwey C, Madhi SA, Dorfman JR. Fetal Transfer of Human Metapneumovirus-Neutralizing Antibodies Is Reduced From Mothers Living With HIV-1. J Pediatric Infect Dis Soc 2022; 11:341-344. [PMID: 35390156 DOI: 10.1093/jpids/piac018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 03/13/2022] [Indexed: 11/14/2022]
Abstract
Transplacental hMPV-neutralizing antibody transfer was reduced from mothers living with HIV-1. However, a comparison of antibody titers at birth between hMPV hospitalization cases at <6 months and matched controls suggested that reduced maternal antibody might not be the primary cause of the previously reported elevated hMPV risk in HIV-1-exposed infants.
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Affiliation(s)
- Lesego M Ramocha
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | | | - Vicky Baillie
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa.,African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Stefan van Nieuwkoop
- Department of Viroscience, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Clare L Cutland
- African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Stephanie Jones
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Andrew Moultrie
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Alane Izu
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa.,African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Charl Verwey
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Pediatrics and Child Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Shabir A Madhi
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa.,African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeffrey R Dorfman
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa.,African Leadership in Vaccinology Expertise (ALIVE), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Division of Medical Virology, Department of Pathology, Stellenbosch University, Cape Town, South Africa
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5
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Kirkpatrick TR, Belitz D, Dorfman JR. Nonhydrodynamic initial conditions are not soon forgotten. Phys Rev E 2021; 104:024111. [PMID: 34525645 DOI: 10.1103/physreve.104.024111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 07/28/2021] [Indexed: 11/07/2022]
Abstract
Solutions to hydrodynamic equations, which are used for a vast variety of physical problems, are assumed to be specified by boundary conditions and initial conditions on the hydrodynamic variables only. Initial values of other variables are assumed to be irrelevant for a hydrodynamic description. We show that this assumption is not correct because of the existence of long-time-tail effects that are ubiquitous in systems governed by hydrodynamic equations. We illustrate this breakdown of a hydrodynamic description by means of the simple example of diffusion in a disordered electron system.
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Affiliation(s)
- T R Kirkpatrick
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - D Belitz
- Department of Physics and Institute for Fundamental Science, University of Oregon, Eugene, Oregon 97403, USA.,Materials Science Institute, University of Oregon, Eugene, Oregon 97403, USA
| | - J R Dorfman
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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6
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Kariuki SM, Selhorst P, Abrahams MR, Rebe K, Williamson C, Dorfman JR. Neutralization sensitivity of genital tract HIV-1: shift in selective milieu shapes the population available to transmit. AIDS 2021; 35:1365-1373. [PMID: 33831907 DOI: 10.1097/qad.0000000000002912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Previous studies indicate that transmitted/founder HIV-1 isolates are sensitive to neutralization by the transmitting donor's antibodies. This is true in at least a subset of sexual transmissions. We investigated whether this selection for neutralization-sensitive variants begins in the genital tract of the donor, prior to transmission. DESIGN Laboratory study. METHODS HIV-1 viruses from semen and blood of two male donors living with HIV-1 were tested for neutralization sensitivity to contemporaneous autologous antibodies. RESULTS In one donor, semen-derived clones (n = 10, geometric mean ID50 = 176) were 1.75-fold [95% confidence interval (CI) 1.11-2.76, P = 0.018] more sensitive than blood-derived clones (n = 12, geometric mean ID50 = 111) to the individual's own contemporaneous neutralizing antibodies. Enhanced overall neutralization sensitivity of the semen-derived clones could not explain the difference because these semen-derived isolates showed a trend of being less sensitive to neutralization by a pool of heterologous clade-matched sera. This relative sensitivity of semen-derived clones was not observed in a second donor who did not exhibit obvious independent HIV-1 replication in the genital tract. A Bayesian analysis suggested that the set of semen sequences that we analysed originated from a blood sequence. CONCLUSION In some instances, selection for neutralization-sensitive variants during HIV-1 transmission begins in the genital tract of the donor and this may be driven by independent HIV-1 replication in this compartment. Thus, a shift in the selective milieu in the male genital tract allows outgrowth of neutralization-sensitive HIV-1 variants, shaping the population of isolates available for transmission to a new host.
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Affiliation(s)
- Samuel Mundia Kariuki
- Division of Immunology, Department of Pathology, University of Cape Town
- International Centre for Genetic Engineering and Biotechnology, Cape Town, Cape Town, South Africa
- Department of Biological Sciences, School of Science, University of Eldoret, Kenya
| | - Philippe Selhorst
- Division of Medical Virology, Department of Pathology, and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town
| | - Melissa-Rose Abrahams
- Division of Medical Virology, Department of Pathology, and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town
| | - Kevin Rebe
- ANOVA Health Institute, Cape Town
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, University of Cape Town
| | - Carolyn Williamson
- Division of Medical Virology, Department of Pathology, and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, University of Cape Town
- Division of Medical Virology, Department of Pathology, University of Stellenbosch, Cape Town, South Africa
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7
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Kirkpatrick TR, Belitz D, Dorfman JR. Rigidity and Superfast Signal Propagation in Fluids and Solids in Non-Equilibrium Steady States. J Phys Chem B 2021; 125:7499-7507. [PMID: 34191519 DOI: 10.1021/acs.jpcb.0c11283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the 1980s, it was theoretically predicted that correlations of various observables in a fluid in a non-equilibrium steady state (NESS) are extraordinarily long-ranged, extending, in a well-defined sense, over the size of the system. This is to be contrasted with correlations in an equilibrium fluid, whose range is typically just a few particle diameters. These NESS correlations were later confirmed by numerous experimental studies. Unlike long-ranged correlations at critical points, these correlations are generic in the sense that they exist for any temperature as long as the system is in a NESS. In equilibrium systems, generic long-ranged correlations are caused by spontaneously broken continuous symmetries and are associated with a generalized rigidity, which in turn leads to a new propagating excitation or mode. For example, in a solid, spatial rigidity leads to transverse sound waves, while, in a superfluid, phase rigidity leads to temperature waves known as second sound at finite temperatures and phonons at zero temperature. More generally, long-ranged spatial correlations imply rigidity irrespective of their physical origin. This implies that a fluid in a NESS should also display a type of rigidity and related anomalous transport behavior. Here we show that this is indeed the case. For the particular case of a simple fluid in a constant temperature gradient, the anomalous transport behavior takes the form of a super-diffusive spread of a constant-pressure temperature perturbation. We also discuss the case of an elastic solid, where we predict a spread that is faster than ballistic.
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Affiliation(s)
- T R Kirkpatrick
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States
| | - D Belitz
- Department of Physics, Institute for Fundamental Science, and Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
| | - J R Dorfman
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, United States
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8
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Tongo M, Martin DP, Dorfman JR. Elucidation of Early Evolution of HIV-1 Group M in the Congo Basin Using Computational Methods. Genes (Basel) 2021; 12:genes12040517. [PMID: 33918115 PMCID: PMC8065694 DOI: 10.3390/genes12040517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 11/16/2022] Open
Abstract
The Congo Basin region is believed to be the site of the cross-species transmission event that yielded HIV-1 group M (HIV-1M). It is thus likely that the virus has been present and evolving in the region since that cross-species transmission. As HIV-1M was only discovered in the early 1980s, our directly observed record of the epidemic is largely limited to the past four decades. Nevertheless, by exploiting the genetic relatedness of contemporary HIV-1M sequences, phylogenetic methods provide a powerful framework for investigating simultaneously the evolutionary and epidemiologic history of the virus. Such an approach has been taken to find that the currently classified HIV-1 M subtypes and Circulating Recombinant Forms (CRFs) do not give a complete view of HIV-1 diversity. In addition, the currently identified major HIV-1M subtypes were likely genetically predisposed to becoming a major component of the present epidemic, even before the events that resulted in the global epidemic. Further efforts have identified statistically significant hot- and cold-spots of HIV-1M subtypes sequence inheritance in genomic regions of recombinant forms. In this review we provide ours and others recent findings on the emergence and spread of HIV-1M variants in the region, which have provided insights into the early evolution of this virus.
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Affiliation(s)
- Marcel Tongo
- Center for Research on Emerging and Re-Emerging Diseases (CREMER), Institute of Medical Research and Study of Medicinal Plants (IMPM), Yaoundé, Cameroon
- Correspondence:
| | - Darren P. Martin
- Division of Computational Biology, Department of Integrative Biomedical Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa;
| | - Jeffrey R. Dorfman
- Division of Medical Virology, School of Pathology, Faculty of Health Sciences, Stellenbosch University, Cape Town 7505, South Africa;
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9
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Dorfman JR, Balla SR, Pathirana J, Groome MJ, Madhi SA, Moore PL. In utero human cytomegalovirus infection is associated with increased levels of putatively protective maternal antibodies in nonprimary infection: evidence for boosting but not protection. Clin Infect Dis 2021; 73:e981-e987. [PMID: 33560335 DOI: 10.1093/cid/ciab099] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 02/02/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Although primary maternal cytomegalovirus infections are associated with higher risk of in utero transmission, most fetal infections worldwide result from nonprimary maternal infections. Antibodies directed at glycoprotein B and the gH/gL/pUL128-130-131 pentamer can neutralize virus, and higher levels of antibody directed at several particular pentamer epitopes defined by monoclonal antibodies (mAbs) are associated with reduced risk of fetal cytomegalovirus transmission during primary maternal infection. This had not been explored in maternal nonprimary infection. METHODS In a setting where most maternal cytomegalovirus infections are nonprimary, 42 mothers of infants with congenital CMV infections (transmitters) were compared to 75 cytomegalovirus-seropositive mothers whose infants were cytomegalovirus-uninfected (nontransmitters). Control infants were matched by sex, maternal HIV status and gestational age. We measured the ability of maternal antibodies to block three key pentameric epitopes: one in the gH subunit, another straddling UL130/UL131 and the third straddling gH/gL/UL128/UL130. We tested if levels of antibodies directed at these epitopes were higher in nontransmitters compared to transmitters. RESULTS Levels of all three putatively protective pentamer-directed antibodies were significantly higher in transmitters compared to nontransmitters. In contrast, antibodies targeting an epitope on glycoprotein B were not different. Total antibody specific for pentamer and for gB were also higher in transmitters. CONCLUSIONS We found no evidence that higher levels of any CMV-specific antibodies were associated with reduced risk of congenital CMV infection in nonprimary maternal infection. Instead, we found higher maternal antibody targeting epitopes on CMV pentamer in transmitters than nontransmitters, providing evidence for antibody boosting but not protection.
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Affiliation(s)
- Jeffrey R Dorfman
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, South Africa
- Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
- Division of Medical Virology, Department of Pathology, Stellenbosch University, Cape Town, South Africa
| | - Sashkia R Balla
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jayani Pathirana
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, South Africa
- Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Michelle J Groome
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, South Africa
- Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Shabir A Madhi
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, South Africa
- Department of Science/National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Penny L Moore
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Antibody Immunity Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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10
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Moyo T, Guleid FH, Schomaker M, Williamson C, Dorfman JR. HIV-1 Subtype C Tier 3 Viruses Have Increased Infectivity Compared to Tier 2 Viruses. AIDS Res Hum Retroviruses 2020; 36:1010-1019. [PMID: 32935560 DOI: 10.1089/aid.2020.0124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A primary concern of an antibody-based HIV-1 therapy is the virus' ability to rapidly escape antibody responses. Therefore, we investigated the relationships between antibody neutralization sensitivity, viral phenotype, and infectivity in 13 subtype C viruses using a HeLa transfectant-based assay. We observed that the seven tier 3 viruses exhibited higher infectivity than the tier 2 viruses, suggesting that higher neutralization resistance did not have a substantial entry cost. There was no relationship between neutralization resistance and susceptibility to entry inhibitors Maraviroc, PSC RANTES, or the fusion inhibitor T20, indicating that neutralization resistance may not alter these inhibitor target sites. By analyzing glycosylation patterns in 82 subtype C viruses, we found that the presence of an N-linked glycan motif at position N413 and its absence at N332 were the most important predictors of neutralization resistance. In a set of 200 subtype C viruses, tier 3 strains were more resistant than tier 2 or 1B viruses to several broadly neutralizing monoclonal antibodies targeting three different epitopes. This suggests that it is unlikely that resistance to antibodies targeting a single epitope drives overall resistance. In the context of an antibody-based intervention, highly resistant viruses with increased infectivity, circulating in the population, could hinder HIV-1 control since entry of tier 3 viruses is not always selected against. Therefore, for any long-term antibody-based intervention to be globally relevant, it must elicit responses that limit the occurrence of resistance.
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Affiliation(s)
- Thandeka Moyo
- Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Fatuma H. Guleid
- Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Michael Schomaker
- Centre for Infectious Disease Epidemiology and Research, University of Cape Town, Cape Town, South Africa
| | - Carolyn Williamson
- Division of Medical Virology and Institute of Infectious Disease and Molecular Medicine, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- National Health Laboratory Service, Cape Town, South Africa
| | - Jeffrey R. Dorfman
- Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Division of Medical Virology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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11
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Madhi SA, Mutsaerts EA, Izu A, Boyce W, Bhikha S, Ikulinda BT, Jose L, Koen A, Nana AJ, Moultrie A, Roalfe L, Hunt A, Goldblatt D, Cutland CL, Dorfman JR. Immunogenicity of a single-dose compared with a two-dose primary series followed by a booster dose of ten-valent or 13-valent pneumococcal conjugate vaccine in South African children: an open-label, randomised, non-inferiority trial. Lancet Infect Dis 2020; 20:1426-1436. [PMID: 32857992 PMCID: PMC7689288 DOI: 10.1016/s1473-3099(20)30289-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 02/04/2020] [Accepted: 04/02/2020] [Indexed: 11/24/2022]
Abstract
Background Routine childhood immunisation with pneumococcal conjugate vaccine (PCV) has changed the epidemiology of pneumococcal disease across age groups, providing an opportunity to reconsider PCV dosing schedules. We aimed to evaluate the post-booster dose immunogenicity of ten-valent (PCV10) and 13-valent (PCV13) PCVs between infants randomly assigned to receive a single-dose compared with a two-dose primary series. Methods We did an open-label, non-inferiority, randomised study in HIV-unexposed infants at a single centre in Soweto, South Africa. Infants were randomly assigned to receive one priming dose of PCV10 or PCV13 at ages 6 weeks (6w + 1 PCV10 and 6w + 1 PCV13 groups) or 14 weeks (14w + 1 PCV10 and 14w + 1 PCV13 groups) or two priming doses of PCV10 or PCV13, one each at ages 6 weeks and 14 weeks (2 + 1 PCV10 and 2 + 1 PCV13 groups); all participants then received a booster dose of PCV10 or PCV13 at 40 weeks of age. The primary endpoint was geometric mean concentrations (GMCs) of serotype-specific IgG 1 month after the booster dose, which was assessed in all participants who received PCV10 or PCV13 as per the assigned randomisation group and for whom laboratory results were available at that timepoint. The 1 + 1 vaccine schedule was considered non-inferior to the 2 + 1 vaccine schedule if the lower bound of the 96% CI for the GMC ratio was greater than 0·5 for at least ten PCV13 serotypes and eight PCV10 serotypes. Safety was a secondary endpoint. This trial is registered with ClinicalTrials.gov (NCT02943902) and is ongoing. Findings Of 1695 children assessed, 600 were enrolled and randomly assigned to one of the six groups between Jan 9 and Sept 20, 2017; 542 were included in the final analysis of the primary endpoint (86–93 per group). For both PCV13 and PCV10, a 1+1 dosing schedule (either beginning at 6 or 14 weeks) was non-inferior to a 2 + 1 schedule. For PCV13, the lower limit of the 96% CI for the ratio of GMCs between the 1 + 1 and 2 + 1 groups was higher than 0·5 for ten serotypes in the 6w+1 group (excluding 6B, 14, and 23F) and 11 serotypes in the 14w + 1 group (excluding 6B and 23F). For PCV10, the lower limit of the 96% CI for the ratio of GMCs was higher than 0·5 for all ten serotypes in the 6w+1 and 14w + 1 groups. 84 serious adverse events were reported in 72 (12%) of 600 participants. 15 occurred within 28 days of vaccination, but none were considered to be related to PCV injection. There were no cases of culture-confirmed invasive pneumococcal disease. Interpretation The non-inferiority in post-booster immune responses following a single-dose compared with a two-dose primary series of PCV13 or PCV10 indicates the potential for reducing PCV dosing schedules from a 2 + 1 to 1 + 1 series in low-income and middle-income settings with well established PCV immunisation programmes. Funding The Bill & Melinda Gates Foundation (OPP1 + 152352).
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Affiliation(s)
- Shabir A Madhi
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa.
| | - Eleonora Aml Mutsaerts
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Alane Izu
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Welekazi Boyce
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Sutika Bhikha
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Benit T Ikulinda
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Lisa Jose
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Anthonet Koen
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Amit J Nana
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Andrew Moultrie
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Lucy Roalfe
- Immunobiology Section, University College London, Great Ormond Street Institute of Child Health Biomedical Research Centre, London, UK
| | - Adam Hunt
- Immunobiology Section, University College London, Great Ormond Street Institute of Child Health Biomedical Research Centre, London, UK
| | - David Goldblatt
- Immunobiology Section, University College London, Great Ormond Street Institute of Child Health Biomedical Research Centre, London, UK
| | - Clare L Cutland
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
| | - Jeffrey R Dorfman
- South African Medical Research Council Vaccines and Infectious Diseases Analytical Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa; Department of Science, National Research Foundation: Vaccine Preventable Diseases, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa
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12
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Kariuki SM, Selhorst P, Anthony C, Matten D, Abrahams MR, Martin DP, Ariën KK, Rebe K, Williamson C, Dorfman JR. Compartmentalization and Clonal Amplification of HIV-1 in the Male Genital Tract Characterized Using Next-Generation Sequencing. J Virol 2020; 94:e00229-20. [PMID: 32269124 PMCID: PMC7307092 DOI: 10.1128/jvi.00229-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/16/2020] [Indexed: 12/17/2022] Open
Abstract
Compartmentalization of HIV-1 between the systemic circulation and the male genital tract may have a substantial impact on which viruses are available for sexual transmission to new hosts. We studied compartmentalization and clonal amplification of HIV-1 populations between the blood and the genital tract from 10 antiretroviral-naive men using Illumina MiSeq with a PrimerID approach. We found evidence of some degree of compartmentalization in every study participant, unlike previous studies, which collectively showed that only ∼50% of analyzed individuals exhibited compartmentalization of HIV-1 lineages between the male genital tract (MGT) and blood. Using down-sampling simulations, we determined that this disparity can be explained by differences in sampling depth in that had we sequenced to a lower depth, we would also have found compartmentalization in only ∼50% of the study participants. For most study participants, phylogenetic trees were rooted in blood, suggesting that the male genital tract reservoir is seeded by incoming variants from the blood. Clonal amplification was observed in all study participants and was a characteristic of both blood and semen viral populations. We also show evidence for independent viral replication in the genital tract in the individual with the most severely compartmentalized HIV-1 populations. The degree of clonal amplification was not obviously associated with the extent of compartmentalization. We were also unable to detect any association between history of sexually transmitted infections and level of HIV-1 compartmentalization. Overall, our findings contribute to a better understanding of the dynamics that affect the composition of virus populations that are available for transmission.IMPORTANCE Within an individual living with HIV-1, factors that restrict the movement of HIV-1 between different compartments-such as between the blood and the male genital tract-could strongly influence which viruses reach sites in the body from which they can be transmitted. Using deep sequencing, we found strong evidence of restricted HIV-1 movements between the blood and genital tract in all 10 men that we studied. We additionally found that neither the degree to which particular genetic variants of HIV-1 proliferate (in blood or genital tract) nor an individual's history of sexually transmitted infections detectably influenced the degree to which virus movements were restricted between the blood and genital tract. Last, we show evidence that viral replication gave rise to a large clonal amplification in semen in a donor with highly compartmentalized HIV-1 populations, raising the possibility that differential selection of HIV-1 variants in the genital tract may occur.
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Affiliation(s)
- Samuel Mundia Kariuki
- Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
- Department of Biological Sciences, School of Science, University of Eldoret, Eldoret, Kenya
| | - Philippe Selhorst
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Colin Anthony
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - David Matten
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Melissa-Rose Abrahams
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Darren P Martin
- Computational Biology Group, Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Insitute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Kevin K Ariën
- Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Kevin Rebe
- Anova Health Institute, Cape Town, South Africa
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, University of Cape Town, Cape Town, South Africa
| | - Carolyn Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Insitute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Division of Medical Virology, Department of Pathology, Stellenbosch University, Cape Town, South Africa
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13
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Kariuki SM, Selhorst P, Norman J, Cohen K, Rebe K, Williamson C, Dorfman JR. Detectable HIV-1 in semen in individuals with very low blood viral loads. Virol J 2020; 17:29. [PMID: 32138741 PMCID: PMC7059658 DOI: 10.1186/s12985-020-01300-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Background Several reports indicate that a portion (5–10%) of men living with HIV-1 intermittently shed HIV-1 RNA into seminal plasma while on long term effective antiretroviral therapy (ART). This is highly suggestive of an HIV-1 reservoir in the male genital tract. However, the status of this reservoir in men living with HIV-1 who are not under treatment is underexplored and has implications for understanding the origins and evolution of the reservoir. Finding Forty-three HIV-1 positive, antiretroviral therapy naïve study participants attending a men’s health clinic were studied. Semen viral loads and blood viral loads were generally correlated, with semen viral loads generally detected in individuals with blood viral loads > 10,000 cp/ml. However, we found 1 individual with undetectable viral loads (<20cp/ml) and 2 individuals with very low blood viral load (97 and 333cp/ml), but with detectable HIV-1 in semen (485–1157 copies/semen sample). Blood viral loads in the first individual were undetectable when tested three times over the prior 5 years. Conclusions Semen HIV-1 viral loads are usually related to blood viral loads, as we confirm. Nonetheless, this was not true in a substantial minority of individuals suggesting unexpectedly high levels of replication in the male genital tract in a few individuals, despite otherwise effective immune control. This may reflect establishment of a local reservoir of HIV-1 populations.
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Affiliation(s)
- Samuel Mundia Kariuki
- Division of Immunology, Department of Pathology, University of Cape Town, Anzio Rd, Observatory, Cape Town, 7925, South Africa.,International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Department of Biological Sciences, School of Science, University of Eldoret, Eldoret, Kenya
| | - Philippe Selhorst
- Division of Medical Virology, Department of Pathology, University of Cape Town, Cape Town, South Africa.,Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Jennifer Norman
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Karen Cohen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Kevin Rebe
- Anova Health Institute, Cape Town, South Africa.,Division of Infectious Diseases and HIV Medicine, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Carolyn Williamson
- Division of Medical Virology, Department of Pathology, University of Cape Town, Cape Town, South Africa.,Institute for Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.,National Health Laboratory Service, Johannesburg, South Africa
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, University of Cape Town, Anzio Rd, Observatory, Cape Town, 7925, South Africa. .,Division of Virology, Faculty of Medicine and Health Sciences, Stellenbosch University, Parow, South Africa.
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14
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Ferreira RC, Grant OC, Moyo T, Dorfman JR, Woods RJ, Travers SA, Wood NT. Structural Rearrangements Maintain the Glycan Shield of an HIV-1 Envelope Trimer After the Loss of a Glycan. Sci Rep 2018; 8:15031. [PMID: 30302011 PMCID: PMC6177452 DOI: 10.1038/s41598-018-33390-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/26/2018] [Indexed: 02/06/2023] Open
Abstract
The HIV-1 envelope (Env) glycoprotein is the primary target of the humoral immune response and a critical vaccine candidate. However, Env is densely glycosylated and thereby substantially protected from neutralisation. Importantly, glycan N301 shields V3 loop and CD4 binding site epitopes from neutralising antibodies. Here, we use molecular dynamics techniques to evaluate the structural rearrangements that maintain the protective qualities of the glycan shield after the loss of glycan N301. We examined a naturally occurring subtype C isolate and its N301A mutant; the mutant not only remained protected against neutralising antibodies targeting underlying epitopes, but also exhibited an increased resistance to the VRC01 class of broadly neutralising antibodies. Analysis of this mutant revealed several glycans that were responsible, independently or through synergy, for the neutralisation resistance of the mutant. These data provide detailed insight into the glycan shield’s ability to compensate for the loss of a glycan, as well as the cascade of glycan movements on a protomer, starting at the point mutation, that affects the integrity of an antibody epitope located at the edge of the diminishing effect. These results present key, previously overlooked, considerations for HIV-1 Env glycan research and related vaccine studies.
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Affiliation(s)
- Roux-Cil Ferreira
- South African Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa
| | - Oliver C Grant
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States
| | - Thandeka Moyo
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa.,Division of Immunology, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States
| | - Simon A Travers
- South African Medical Research Council Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa
| | - Natasha T Wood
- University of Cape Town, UCT Computational Biology Group, Department of Integrated Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa.
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15
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Moyo T, Ereño-Orbea J, Jacob RA, Pavillet CE, Kariuki SM, Tangie EN, Julien JP, Dorfman JR. Molecular Basis of Unusually High Neutralization Resistance in Tier 3 HIV-1 Strain 253-11. J Virol 2018; 92:e02261-17. [PMID: 29618644 PMCID: PMC6026760 DOI: 10.1128/jvi.02261-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 02/26/2018] [Indexed: 01/06/2023] Open
Abstract
Understanding the mechanisms used by HIV-1 to evade antibody neutralization may contribute to the design of a high-coverage vaccine. The tier 3 virus 253-11 is poorly neutralized by subtype-matched and subtype C sera, even compared to other tier 3 viruses, and is also recognized poorly by V3/glycan-targeting monoclonal antibodies (MAbs). We found that sequence polymorphisms in the V3 loop and N-linked glycosylation sites contribute only minimally to the high neutralization resistance of 253-11. Interestingly, the 253-11 membrane-proximal external region (MPER) is rarely recognized by sera in the context of the wild-type virus but is commonly recognized in the context of an HIV-2 chimera, suggesting steric or kinetic hindrance of binding to MPER in the native envelope (Env). Mutations in the 253-11 MPER, which were previously reported to increase the lifetime of the prefusion Env conformation, affected the resistance of 253-11 to antibodies targeting various epitopes on HIV-1 Env, presumably destabilizing its otherwise stable, closed trimer structure. To gain insight into the structure of 253-11, we constructed and crystallized a recombinant 253-11 SOSIP trimer. The resulting structure revealed that the heptad repeat helices in gp41 are drawn in close proximity to the trimer axis and that gp120 protomers also showed a relatively compact disposition around the trimer axis. These observations give substantial insight into the molecular features of an envelope spike from a tier 3 virus and into possible mechanisms that may contribute to its unusually high neutralization resistance.IMPORTANCE HIV-1 isolates that are highly resistant to broadly neutralizing antibodies could limit the efficacy of an antibody-based vaccine. We studied 253-11, which is highly resistant to commonly elicited neutralizing antibodies. To further understand its resistance, we made mutations that are known to delay fusion and thus increase the time that the virus spends in the open conformation following CD4 binding. Interestingly, we found that these mutations affect the 253-11 envelope (Env) spike before CD4 binding, presumably by destabilizing the trimer structure. To gain further information about the structure of the 253-11 Env trimer, we generated a recombinant 253-11 SOSIP trimer. The crystal structure of the SOSIP trimer revealed that the gp41 helices and the gp120 protomers were drawn in toward the center of the molecule compared to most solved HIV-1 Env structures. These observations provide insight into the distinct molecular features of a tier 3 envelope spike.
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Affiliation(s)
- Thandeka Moyo
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - June Ereño-Orbea
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Rajesh Abraham Jacob
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Clara E Pavillet
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Samuel Mundia Kariuki
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
- Department of Biological Science, University of Eldoret, Eldoret, Kenya
| | - Emily N Tangie
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Jean-Philippe Julien
- Program in Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
- Division of Immunology, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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16
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Tongo M, Harkins GW, Dorfman JR, Billings E, Tovanabutra S, de Oliveira T, Martin DP. Unravelling the complicated evolutionary and dissemination history of HIV-1M subtype A lineages. Virus Evol 2018; 4:vey003. [PMID: 29484203 PMCID: PMC5819727 DOI: 10.1093/ve/vey003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Subtype A is one of the rare HIV-1 group M (HIV-1M) lineages that is both widely distributed throughout the world and persists at high frequencies in the Congo Basin (CB), the site where HIV-1M likely originated. This, together with its high degree of diversity suggests that subtype A is amongst the fittest HIV-1M lineages. Here we use a comprehensive set of published near full-length subtype A sequences and A-derived genome fragments from both circulating and unique recombinant forms (CRFs/URFs) to obtain some insights into how frequently these lineages have independently seeded HIV-1M sub-epidemics in different parts of the world. We do this by inferring when and where the major subtype A lineages and subtype A-derived CRFs originated. Following its origin in the CB during the 1940s, we track the diversification and recombination history of subtype A sequences before and during its dissemination throughout much of the world between the 1950s and 1970s. Collectively, the timings and numbers of detectable subtype A recombination and dissemination events, the present broad global distribution of the sub-epidemics that were seeded by these events, and the high prevalence of subtype A sequences within the regions where these sub-epidemics occurred, suggest that ancestral subtype A viruses (and particularly sub-subtype A1 ancestral viruses) may have been genetically predisposed to become major components of the present epidemic.
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Affiliation(s)
- Marcel Tongo
- KwaZulu-Natal Research Innovation and Sequencing Platform (Krisp), School of Laboratory Medicine and Medical Sciences, College of Health Sciences, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban 4041, South Africa
- Division of Computational Biology, Department of Integrative Biomedical Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- Center of Research for Emerging and Re-Emerging Diseases (CREMER), Institute of Medical Research and Study of Medicinal Plants (IMPM), Yaoundé, Cameroon
| | - Gordon W Harkins
- South African MRC Bioinformatics Unit, South African National Bioinformatics Institute, University of the Western Cape, Bellville 7535, South Africa
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- Division of Immunology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa
| | - Erik Billings
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910–7500, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD 20910–7500, USA
| | - Sodsai Tovanabutra
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910–7500, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD 20910–7500, USA
| | - Tulio de Oliveira
- KwaZulu-Natal Research Innovation and Sequencing Platform (Krisp), School of Laboratory Medicine and Medical Sciences, College of Health Sciences, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Darren P Martin
- Division of Computational Biology, Department of Integrative Biomedical Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
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17
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Abstract
It is well established that most new systemic infections of HIV-1 can be traced back to one or a limited number of founder viruses. Usually, these founders are more closely related to minor HIV-1 populations in the blood of the presumed donor than to more abundant lineages. This has led to the widely accepted idea that transmission selects for viral characteristics that facilitate crossing the mucosal barrier of the recipient’s genital tract, although the specific selective forces or advantages are not completely defined. However, there are other steps along the way to becoming a founder virus at which selection may occur. These steps include the transition from the donor’s general circulation to the genital tract compartment, survival within the transmission fluid, and establishment of a nascent stable local infection in the recipient’s genital tract. Finally, there is the possibility that important narrowing events may also occur during establishment of systemic infection. This is suggested by the surprising observation that the number of founder viruses detected after transmission in intravenous drug users is also limited. Although some of these steps may be heavily selective, others may result mostly in a stochastic narrowing of the available founder pool. Collectively, they shape the initial infection in each recipient.
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Affiliation(s)
- Samuel Mundia Kariuki
- Division of Immunology, Department of Pathology, Falmouth 3.25, University of Cape Town, Anzio Rd, Observatory, Cape Town, 7925, South Africa.,International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Department of Biological Sciences, University of Eldoret, Eldoret, Kenya
| | - Philippe Selhorst
- Division of Medical Virology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - Kevin K Ariën
- Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Jeffrey R Dorfman
- Division of Immunology, Department of Pathology, Falmouth 3.25, University of Cape Town, Anzio Rd, Observatory, Cape Town, 7925, South Africa.
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18
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Tongo M, Dorfman JR, de Oliveira T, Martin DP. A40 Persistent circulation of highly divergent HIV-1M lineages in the Congo Basin Region. Virus Evol 2017; 3:vew036.039. [PMID: 28845263 PMCID: PMC5565973 DOI: 10.1093/ve/vew036.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Affiliation(s)
- M Tongo
- Africa Centre for Population Health, University of KwaZulu-Natal, South Africa
| | - J R Dorfman
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Tulio de Oliveira
- Africa Centre for Population Health, University of KwaZulu-Natal, South Africa
| | - D P Martin
- Division of Computational Biology and Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, South Africa
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19
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Kirkpatrick TR, Dorfman JR, Sengers JV. Work, work fluctuations, and the work distribution in a thermal nonequilibrium steady state. Phys Rev E 2016; 94:052128. [PMID: 27967150 DOI: 10.1103/physreve.94.052128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Indexed: 11/07/2022]
Abstract
Long-ranged correlations generically exist in nonequilibrium fluid systems. In the case of a nonequilibrium steady state caused by a temperature gradient, the correlations are especially long-ranged and strong. The anomalous light scattering predicted to exist in these systems is well-confirmed by numerous experiments. Recently, the Casimir force or pressure due to these fluctuations or correlations has been discussed in great detail. In this paper, the notion of a Casimir work is introduced, and an alternative way to measure the nonequilibrium Casimir force is suggested. In particular, the nonequilibrium Casimir force is related to nonequilibrium heat, and not, as in equilibrium, to a volume derivative of an average energy. The nonequilibrium work fluctuations are determined and shown to be very anomalous compared to equilibrium work fluctuations. The nonequilibrium work distribution is also computed, and it is contrasted with work distributions in systems with short-range correlations. Again, there is a striking difference in the two cases. Formal theories of work and work distributions in nonequilibrium steady states are not explicit enough to illustrate any of these interesting features.
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Affiliation(s)
- T R Kirkpatrick
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - J R Dorfman
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - J V Sengers
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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20
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Tongo M, Dorfman JR, Abrahams MR, Mpoudi-Ngole E, Burgers WA, Martin DP. Near full-length HIV type 1M genomic sequences from Cameroon : Evidence of early diverging under-sampled lineages in the country. Evol Med Public Health 2015; 2015:254-65. [PMID: 26354000 PMCID: PMC4600344 DOI: 10.1093/emph/eov022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/25/2015] [Indexed: 12/30/2022]
Abstract
Background: Cameroon is the country in which HIV-1 group M (HIV-1M) likely originated and is today a major hotspot of HIV-1M genetic diversity. It remains unclear, however, whether the highly divergent HIV-1M lineages found in this country arose during the earliest phases of the global HIV-1M epidemic, or whether they arose more recently as a result of recombination events between globally circulating HIV-1M lineages. Methodology: To differentiate between these two possibilities, we performed phylogenetic analyses of the near full genome sequences of nine newly sequenced divergent HIV-1M isolates and 15 previously identified, apparently unique recombinant forms (URFs) from Cameroon. Results: Although two of the new genome sequences were clearly classifiable within subtype G, the remaining seven were highly divergent and phylogenetically branched either outside of, or very near the bases of clades containing the well characterised globally circulating viral lineages that they were most closely related to. Recombination analyses further revealed that these divergent viruses were likely complex URFs. We show, however that substantial portions (>1 Kb) of three of the new genome sequences and 15 of the previously characterised Cameroonian URFs have apparently been derived from divergent parental viruses that branch phylogenetically near the bases of the major HIV-1M clades. Conclusions and implications: Our analyses indicate the presence in Cameroon of contemporary descendants of numerous early-diverging HIV-1M lineages. Further efforts to sample and sequence viruses from such lineages could be crucial both for retracing the earliest evolutionary steps during the emergence of HIV-1M in humans, and accurately reconstructing the ancestral sequences of the major globally circulating HIV-1M lineages.
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Affiliation(s)
- Marcel Tongo
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa; Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Division of Medical Virology, Department of Pathology and Institute of Medical Research and Study of Medicinal plants (IMPM), Yaoundé, Cameroon
| | - Jeffrey R Dorfman
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa; Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | - Eitel Mpoudi-Ngole
- Institute of Medical Research and Study of Medicinal plants (IMPM), Yaoundé, Cameroon
| | | | - Darren P Martin
- Division of Computational Biology, Department of Integrated Biology Sciences and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; and
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21
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Abstract
Nonequilibrium and equilibrium fluid systems differ due to the existence of long-range correlations in nonequilibrium that are not present in equilibrium, except at critical points. Here we examine fluctuations of the temperature, of the pressure tensor, and of the heat current in a fluid maintained in a nonequilibrium stationary state (NESS) with a fixed temperature gradient, a system in which the nonequilibrium correlations are especially long-ranged. For this particular NESS, our results show that (i) the mean-squared fluctuations in nonequilibrium differ markedly in their system-size scaling compared to their equilibrium counterparts, and (ii) there are large, nonlocal correlations of the normal stress in this NESS. These terms provide important corrections to the fluctuating normal stress in linearized Landau-Lifshitz fluctuating hydrodynamics.
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Affiliation(s)
- T R Kirkpatrick
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - J R Dorfman
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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22
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Tongo M, Essomba RG, Nindo F, Abrahams F, Nanfack AJ, Fokam J, Takou D, Torimiro JN, Mpoudi-Ngole E, Burgers WA, Martin DP, Dorfman JR. Phylogenetics of HIV-1 subtype G env: Greater complexity and older origins than previously reported. Infect Genet Evol 2015; 35:9-18. [PMID: 26190450 DOI: 10.1016/j.meegid.2015.07.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 12/16/2022]
Abstract
HIV-1 subtype G has played an early and central role in the emergent complexity of the HIV-1 group M (HIV-1M) epidemic in central/west Africa. Here, we analysed new subtype G env sequences sampled from 8 individuals in Yaoundé, Cameroon during 2007-2010, together with all publically available subtype G-attributed full-length env sequences with known sampling dates and locations. We inferred that the most recent common ancestor (MRCA) of the analysed subtype G env sequences most likely occurred in ∼1953 (95% Highest Posterior Density interval [HPD] 1939-1963): about 15 years earlier than previous estimates. We found that the subtype G env phylogeny has a complex structure including seven distinct lineages, each likely dating back to the late 1960s or early 1970s. Sequences from Angola, Gabon and the Democratic Republic of Congo failed to group consistently in these lineages, possibly because they are related to more ancient sequences that are poorly sampled. The circulating recombinant form (CRF), CRF06_cpx env sequences but not CRF25_cpx env sequences are phylogenetically nested within the subtype G clade. This confirms that the CRF06_cpx env plausibly was derived through recombination from a subtype G parent, and suggests that the CRF25_cpx env was likely derived from an HIV-1M lineage related to the MRCA of subtype G that has remained undiscovered and may be extinct. Overall, this fills important gaps in our knowledge of the early events in the spread of HIV-1M.
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Affiliation(s)
- Marcel Tongo
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa; Division of Immunology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Division of Medical Virology, Faculty of Health Sciences, and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa; Institute of Medical Research and Study of Medicinal plants (IMPM), Yaoundé, Cameroon
| | - René G Essomba
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa; Division of Immunology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Frederick Nindo
- Computational Biology Group, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Fatima Abrahams
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa
| | - Aubin Joseph Nanfack
- Centre International de Référence «Chantal Biya» pour la recherche sur la prévention et la prise en charge du VIH/SIDA (CIRCB), Yaoundé, Cameroon
| | - Joseph Fokam
- Centre International de Référence «Chantal Biya» pour la recherche sur la prévention et la prise en charge du VIH/SIDA (CIRCB), Yaoundé, Cameroon; Faculty of Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy
| | - Desire Takou
- Centre International de Référence «Chantal Biya» pour la recherche sur la prévention et la prise en charge du VIH/SIDA (CIRCB), Yaoundé, Cameroon
| | - Judith N Torimiro
- Centre International de Référence «Chantal Biya» pour la recherche sur la prévention et la prise en charge du VIH/SIDA (CIRCB), Yaoundé, Cameroon; Faculty of Medicine and Biomedical Sciences, University of Yaounde I, Yaounde, Cameroon
| | - Eitel Mpoudi-Ngole
- Institute of Medical Research and Study of Medicinal plants (IMPM), Yaoundé, Cameroon
| | - Wendy A Burgers
- Division of Medical Virology, Faculty of Health Sciences, and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Darren P Martin
- Computational Biology Group, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Jeffrey R Dorfman
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town, South Africa; Division of Immunology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
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23
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Ibinda F, Bauni E, Kariuki SM, Fegan G, Lewa J, Mwikamba M, Boga M, Odhiambo R, Mwagandi K, Seale AC, Berkley JA, Dorfman JR, Newton CRJC. Incidence and risk factors for neonatal tetanus in admissions to Kilifi County Hospital, Kenya. PLoS One 2015; 10:e0122606. [PMID: 25849440 PMCID: PMC4388671 DOI: 10.1371/journal.pone.0122606] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/11/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Neonatal Tetanus (NT) is a preventable cause of mortality and neurological sequelae that occurs at higher incidence in resource-poor countries, presumably because of low maternal immunisation rates and unhygienic cord care practices. We aimed to determine changes in the incidence of NT, characterize and investigate the associated risk factors and mortality in a prospective cohort study including all admissions over a 15-year period at a County hospital on the Kenyan coast, a region with relatively high historical NT rates within Kenya. METHODS We assessed all neonatal admissions to Kilifi County Hospital in Kenya (1999-2013) and identified cases of NT (standard clinical case definition) admitted during this time. Poisson regression was used to examine change in incidence of NT using accurate denominator data from an area of active demographic surveillance. Logistic regression was used to investigate the risk factors for NT and factors associated with mortality in NT amongst neonatal admissions. A subset of sera from mothers (n = 61) and neonates (n = 47) were tested for anti-tetanus antibodies. RESULTS There were 191 NT admissions, of whom 187 (98%) were home deliveries. Incidence of NT declined significantly (Incidence Rate Ratio: 0.85 (95% Confidence interval 0.81-0.89), P<0.001) but the case fatality (62%) did not change over the study period (P = 0.536). Younger infant age at admission (P = 0.001) was the only independent predictor of mortality. Compared to neonatal hospital admittee controls, the proportion of home births was higher among the cases. Sera tested for antitetanus antibodies showed most mothers (50/61, 82%) had undetectable levels of antitetanus antibodies, and most (8/9, 89%) mothers with detectable antibodies had a neonate without protective levels. CONCLUSIONS Incidence of NT in Kilifi County has significantly reduced, with reductions following immunisation campaigns. Our results suggest immunisation efforts are effective if sustained and efforts should continue to expand coverage.
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Affiliation(s)
- Fredrick Ibinda
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Evasius Bauni
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Symon M Kariuki
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Greg Fegan
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Joy Lewa
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Monica Mwikamba
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Mwanamvua Boga
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Rachael Odhiambo
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Kiponda Mwagandi
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
| | - Anna C Seale
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - James A Berkley
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Jeffrey R Dorfman
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa; Division of Immunology, University of Cape Town, Cape Town, South Africa
| | - Charles R J C Newton
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya; Department of Psychiatry, University of Oxford, Oxford, United Kingdom
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24
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Jacob RA, Moyo T, Abrahams F, Pujol BG, Dorfman JR. Shielding of the HIV-1 Envelope Membrane Proximal External Region (MPER) from Antibody. AIDS Res Hum Retroviruses 2014. [DOI: 10.1089/aid.2014.5450.abstract] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Rajesh Abraham Jacob
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
- University of Cape Town, Division of Immunology, Cape Town, South Africa
| | - Thandeka Moyo
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
- University of Cape Town, Division of Immunology, Cape Town, South Africa
| | - Fatima Abrahams
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Berta Grau Pujol
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Jeffrey R. Dorfman
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
- University of Cape Town, Division of Immunology, Cape Town, South Africa
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25
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Moyo T, Jacob RA, Schomaker M, Grau B, Abrahams F, Dorfman JR. HIV-1 Neutralisation Breadth Is Positively Associated with Presence of Anti-MPER Antibodies and Not of Anti-PG9/16-site Antibodies. AIDS Res Hum Retroviruses 2014. [DOI: 10.1089/aid.2014.5453.abstract] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Thandeka Moyo
- Division of Immunology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Rajesh A. Jacob
- Division of Immunology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa
| | - Michael Schomaker
- Centre for Infectious Disease Epidemiology & Research, Cape Town, South Africa
| | - Berta Grau
- International Centre for Genetic Enginnering and Biotechnology, Cape Town, South Africa
| | - Fatima Abrahams
- International Centre for Genetic Enginnering and Biotechnology, Cape Town, South Africa
| | - Jeffrey R. Dorfman
- Division of Immunology, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Enginnering and Biotechnology, Cape Town, South Africa
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26
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Jacob RA, Abrahams F, Tongo M, Schomaker M, Roux P, Ngole EM, Burgers WA, Dorfman JR. Refined identification of neutralization-resistant CRF02_AG viruses and their sensitivity to anti-MPER neutralizing antibodies. Retrovirology 2012. [PMCID: PMC3442060 DOI: 10.1186/1742-4690-9-s2-p77] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Abstract
In T cells, the stochasticity of protein expression could contribute to the useful diversification of biological functions within a clonal population or interfere with accurate antigen discrimination. Combining computer modeling and single-cell measurements, we examined how endogenous variation in the expression levels of signaling proteins might affect antigen responsiveness during T cell activation. We found that the CD8 co-receptor fine-tunes activation thresholds, whereas the soluble hematopoietic phosphatase 1 (SHP-1) digitally regulates cell responsiveness. Stochastic variation in the expression of these proteins generates substantial diversity of activation within a clonal population of T cells, but co-regulation of CD8 and SHP-1 levels ultimately limits this very diversity. These findings reveal how eukaryotic cells can draw on regulated variation in gene expression to achieve phenotypic variability in a controlled manner.
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Affiliation(s)
- Ofer Feinerman
- ImmunoDynamics Group, Program in Computational Biology and Immunology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue – Box 460, New York NY 10065 - USA
| | - Joël Veiga
- ImmunoDynamics Group, Program in Computational Biology and Immunology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue – Box 460, New York NY 10065 - USA
| | - Jeffrey R. Dorfman
- ImmunoDynamics Group, Program in Computational Biology and Immunology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue – Box 460, New York NY 10065 - USA
| | - Ronald N. Germain
- Lymphocyte Biology Section, Laboratory of Immunology, Program in Systems Immunology and Infectious Disease Modeling (PSIIM), National Institute of Allergy and Infectious Diseases, National Institutes of Health, DHHS, Bldg. 10 Rm. 11N311, 10 Center Dr. MSC-1892, Bethesda, MD 20892-1892 – USA
| | - Grégoire Altan-Bonnet
- ImmunoDynamics Group, Program in Computational Biology and Immunology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue – Box 460, New York NY 10065 - USA
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28
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Oleinikov AV, Francis SE, Dorfman JR, Rossnagle E, Balcaitis S, Getz T, Avril M, Gose S, Smith JD, Fried M, Duffy PE. VAR2CSA domains expressed in Escherichia coli induce cross-reactive antibodies to native protein. J Infect Dis 2008; 197:1119-23. [PMID: 18462161 DOI: 10.1086/529526] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The variant surface antigen VAR2CSA is a pregnancy malaria vaccine candidate, but its size and polymorphism are obstacles to development. We expressed 3D7-type VAR2CSA domains in Escherichia coli as insoluble His-tagged proteins (Duffy binding-like [DBL] domains DBL1, DBL3, DBL4, and DBL5) that were denatured and refolded or as soluble glutathione S-transferase-tagged protein (DBL6). Anti-DBL5 antiserum cross-reacted with surface proteins of chondroitin sulfate A (CSA)-binding laboratory strains (3D7-CSA and FCR3-CSA) and a clinical pregnancy malaria isolate, whereas anti-DBL6 antiserum reacted only to 3D7 surface protein. This is the first report that E. coli-expressed VAR2CSA domains induce antibody to native VAR2CSA.
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Affiliation(s)
- Andrew V Oleinikov
- Seattle Biomedical Research Institute, University of Washington, Seattle, USA
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29
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Goussev A, Dorfman JR. Wave packet autocorrelation functions for quantum hard-disk and hard-sphere billiards in the high-energy, diffraction regime. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 74:016204. [PMID: 16907174 DOI: 10.1103/physreve.74.016204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Indexed: 05/11/2023]
Abstract
We consider the time evolution of a wave packet representing a quantum particle moving in a geometrically open billiard that consists of a number of fixed hard-disk or hard-sphere scatterers. Using the technique of multiple collision expansions we provide a first-principle analytical calculation of the time-dependent autocorrelation function for the wave packet in the high-energy diffraction regime, in which the particle's de Broglie wavelength, while being small compared to the size of the scatterers, is large enough to prevent the formation of geometric shadow over distances of the order of the particle's free flight path. The hard-disk or hard-sphere scattering system must be sufficiently dilute in order for this high-energy diffraction regime to be achievable. Apart from the overall exponential decay, the autocorrelation function exhibits a generally complicated sequence of relatively strong peaks corresponding to partial revivals of the wave packet. Both the exponential decay (or escape) rate and the revival peak structure are predominantly determined by the underlying classical dynamics. A relation between the escape rate, and the Lyapunov exponents and Kolmogorov-Sinai entropy of the counterpart classical system, previously known for hard-disk billiards, is strengthened by generalization to three spatial dimensions. The results of the quantum mechanical calculation of the time-dependent autocorrelation function agree with predictions of the semiclassical periodic orbit theory.
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Affiliation(s)
- Arseni Goussev
- Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany
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30
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Dorfman JR, Bejon P, Ndungu FM, Langhorne J, Kortok MM, Lowe BS, Mwangi TW, Williams TN, Marsh K. B Cell Memory to 3Plasmodium falciparumBlood‐Stage Antigens in a Malaria‐Endemic Area. J Infect Dis 2005; 191:1623-30. [PMID: 15838788 DOI: 10.1086/429671] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Accepted: 12/13/2004] [Indexed: 11/03/2022] Open
Abstract
To gain insight into why antibody responses to malarial antigens tend to be short lived, we studied antigen-specific memory B cells from donors in an area where malaria is endemic. We compared antibody and memory B cell responses to tetanus toxoid with those to 3 Plasmodium falciparum candidate vaccine antigens: the C-terminal portion of merozoite surface protein 1 (MSP1(19)), apical membrane antigen 1 (AMA1), and the cysteine-rich interdomain region 1 alpha (CIDR1 alpha ) of a protein from the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. These data are the first to be generated on memory B cells in children who are in the process of acquiring antimalarial immunity, and they reveal defects in B cell memory to P. falciparum antigens. Compared with the results for tetanus toxoid, more donors who were positive for antibody to AMA1 and CIDR1 alpha were negative for memory B cells. These data imply that some exposures to malaria do not result in the establishment of stable populations of circulating antigen-specific memory B cells, suggesting possible mechanisms for the short-lived nature of many anti-malarial antibody responses.
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Affiliation(s)
- Jeffrey R Dorfman
- Kenya Medical Research Institute, Wellcome Trust Research Laboratories, Kilifi, Kenya.
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31
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Goussev A, Dorfman JR. Lyapunov spreading of semiclassical wave packets for the Lorentz gas: theory and applications. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 71:026225. [PMID: 15783405 DOI: 10.1103/physreve.71.026225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Indexed: 05/24/2023]
Abstract
We consider the quantum-mechanical propagator for a particle moving in a d -dimensional Lorentz gas, with fixed, hard-sphere scatterers. To evaluate this propagator in the semiclassical region, and for times less than the Ehrenfest time, we express its effect on an initial Gaussian wave packet in terms of quantities analogous to those used to describe the exponential separation of trajectories in the classical version of this system. This result relates the spread of the wave packet to the rate of separation of classical trajectories, characterized by positive Lyapunov exponents. We consider applications of these results, first to illustrate the behavior of the wave-packet autocorrelation functions for wave packets on periodic orbits. The autocorrelation function can be related to the fidelity, or Loschmidt echo, for the special case that the perturbation is a small change in the mass of the particle. An exact expression for the fidelity, appropriate for this perturbation, leads to an analytical result valid over very long time intervals, inversely proportional to the size of the mass perturbation. For such perturbations, we then calculate the long-time echo for semiclassical wave packets on periodic orbits.
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Affiliation(s)
- Arseni Goussev
- Institute for Physical Science and Technology and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
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32
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Nyakeriga AM, Troye-Blomberg M, Dorfman JR, Alexander ND, Bäck R, Kortok M, Chemtai AK, Marsh K, Williams TN. Iron Deficiency and Malaria among Children Living on the Coast of Kenya. J Infect Dis 2004; 190:439-47. [PMID: 15243915 DOI: 10.1086/422331] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2003] [Accepted: 02/10/2004] [Indexed: 11/03/2022] Open
Abstract
Both iron deficiency and malaria are common in much of sub-Saharan Africa, and the interaction between these conditions is complex. To investigate the association between nutritional iron status, immunoglobulins, and clinical Plasmodium falciparum malaria, we determined the incidence of malaria in a cohort of children between the ages of 8 months and 8 years who were living on the Kenyan coast. Biochemical iron status and malaria-specific immune responses were determined during 2 cross-sectional surveys. We found that the incidence of clinical malaria was significantly lower among iron-deficient children (incidence-rate ratio [IRR], 0.70; 95% confidence interval [CI], 0.51-0.99; P<.05), that the incidence of malaria was significantly associated with plasma ferritin concentration (IRR for log ferritin concentration, 1.48; 95% CI, 1.01-2.17; P<.05), and that iron status was strongly associated with a range of malaria-specific immunoglobulins. We conclude that iron deficiency was associated with protection from mild clinical malaria in our cohort of children in coastal Kenya and discuss possible mechanisms for this protection.
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Affiliation(s)
- Alice M Nyakeriga
- Kenya Medical Research Institute/Wellcome Trust Programme, Centre for Geographic Medicine Research, Coast, Kilifi District Hospital, Kenya.
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33
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Jamieson AM, Isnard P, Dorfman JR, Coles MC, Raulet DH. Turnover and proliferation of NK cells in steady state and lymphopenic conditions. J Immunol 2004; 172:864-70. [PMID: 14707057 DOI: 10.4049/jimmunol.172.2.864] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To gain insight into NK cell dynamics, we investigated the turnover and proliferation rates of NK cells in normal and lymphopenic conditions. In contrast to previous reports suggesting a very rapid turnover of NK cells, continuous 5-bromo-2'-deoxyuridine (BrdU)-labeling studies demonstrated that the time necessary for labeling 50% of splenic NK cells in mature mice was 17 days, similar to the rate of labeling of memory T cells. In contrast, in young mice, splenic NK cells labeled very rapidly with BrdU, although cell cycle analyses and BrdU pulse-labeling studies suggested that most of this proliferation occurred in a precursor population. A somewhat larger percentage of bone marrow NK cells was cycling, suggesting that these proliferating cells are the precursors of the mostly nondividing or slowly dividing splenic NK cells. Splenic NK cells from mature mice also did not proliferate significantly when transferred to normal mice, but did proliferate when transferred to irradiated mice. Thus, NK cells, like T cells, undergo homeostatic proliferation in a lymphopenic environment. Homeostatic proliferation of NK cells was not dependent on host cell class I molecules or host production of IL-15. Nevertheless, the number of recovered NK cells was much lower in IL-15(-/-) hosts. These results suggest that IL-15 is not essential for homeostatic proliferation of NK cells, but is necessary for survival of the NK cells. Our results provide important basic information concerning the production and replacement of NK cells.
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Affiliation(s)
- Amanda M Jamieson
- Department of Molecular and Cell Biology, and Cancer Research Laboratory, 485 Life Science Addition, University of California-Berkeley, Berkeley, CA 94720, USA
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34
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Abstract
We show that particle transport, as characterized by the equilibrium mean square displacement, in a uniform, quantum multibaker map, is generically ballistic in the long time limit, for any fixed value of Planck's constant. However, for fixed times, the semiclassical limit leads to diffusion. Random matrix theory provides explicit analytical predictions for the mean square displacement of a particle in the system. These results exhibit a crossover from diffusive to ballistic motion, with crossover time on the order of the inverse of Planck's constant. We expect that, for a large class of 1D quantum random walks similar to the quantum multibaker, a sufficient condition for diffusion in the semiclassical limit is classically chaotic dynamics in each cell. The systems described generalize known quantum random walks and may have applications for quantum computation.
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Affiliation(s)
- Daniel K Wójcik
- Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA.
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35
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Abstract
The key role of the thymus in shaping the peripheral T cell receptor (TCR) repertoire has been appreciated for nearly a quarter of a century. For most of that time, a single model has dominated thinking about the physiological role of the positive selection process mediated by TCR recognition of self-peptides and major histocompatibility complex (MHC) molecules. This developmental filter was believed to populate secondary lymphoid tissues with T cells bearing receptors best able to recognize unknown foreign peptides associated with the particular allelic forms of the MHC molecules present in an individual. More recently, self-recognition has been suggested to regulate the viability of naïve T cells. Here we focus on new results indicating that a critical contribution of positive selection to host defense is insuring that each peripheral T cell can use self-recognition to (i) enhance TCR signaling sensitivity upon foreign antigen recognition and (ii) augment the clonal expansion that accompanies limiting foreign antigen display at early points in an infectious process. We also detail new insights into the intracellular signaling circuitry that underlies the effective discrimination between low- and high-quality ligands of the TCR and speculate on how this design might facilitate an additional contribution of self-recognition to T cell activation in the presence of foreign stimuli.
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Affiliation(s)
- Irena Stefanova
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1892, USA
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36
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Stefanová I, Dorfman JR, Germain RN. Self-recognition promotes the foreign antigen sensitivity of naive T lymphocytes. Nature 2002; 420:429-34. [PMID: 12459785 DOI: 10.1038/nature01146] [Citation(s) in RCA: 304] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2002] [Accepted: 09/04/2002] [Indexed: 11/09/2022]
Abstract
Major histocompatibility complex (MHC) class I and II molecules are highly polymorphic proteins that bind and present foreign peptides to the clonally distributed alphabeta receptors (TCR) of T lymphocytes. As a population, the immature T lymphocytes generated in the thymus express a very diverse set of TCR specificities. A process of positive selection filters this broad repertoire to optimize peripheral T cells for antigen recognition in the context of available MHC products. Only those precursor T cells whose TCRs generate an adequate but not excessive signalling response to self-peptides bound to the expressed MHC proteins undergo successful maturation. Here we show that post-thymic self-recognition facilitates the antigen reactivity of mature T cells. Both experimental and physiological interruption of T-cell contact with self-peptide MHC ligands leads to a rapid decline in signalling and response sensitivity to foreign stimuli. Because the adaptive immune system must be recruited early in an infectious process when antigen is limiting, these findings suggest that positive selection ensures predictable T-cell recognition of available self-ligands, which in turn promotes efficient responses to pathogens.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/pharmacology
- Antigens/immunology
- Autoantigens/immunology
- Autoimmunity/drug effects
- CD4-Positive T-Lymphocytes/drug effects
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- DNA-Binding Proteins/genetics
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/immunology
- Ligands
- Mice
- Mice, Transgenic
- Phosphorylation
- Polymorphism, Genetic
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Signal Transduction
- Superantigens/immunology
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Affiliation(s)
- Irena Stefanová
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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37
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Abstract
We introduce a family of models for quantum mechanical, one-dimensional random walks, called quantum multibaker maps (QMB). These are Weyl quantizations of the classical multibaker models previously considered by Gaspard, Tasaki, and others. Depending on the properties of the phase's parametrizing the quantization, we consider only two classes of the QMB maps: uniform and random. Uniform QMB maps are characterized by phases that are the same in every unit cell of the multibaker chain. Random QMB maps have phases that vary randomly from unit cell to unit cell. The eigenstates in the former case are extended while in the latter they are localized. In the uniform case and for large variant Planck's over 2pi, analytic solutions can be obtained for the time-dependent quantum states for periodic chains and for open chains with absorbing boundary conditions. Steady state solutions and the properties of the relaxation to a steady state for a uniform QMB chain in contact with "particle" reservoirs can also be described analytically. The analytical results are consistent with, and confirmed by, results obtained from numerical methods. We report here results for the deep quantum regime (large variant Planck's over 2pi ) of the uniform QMB, as well as some results for the random QMB. We leave the moderate and small variant Planck's over 2pi results as well as further consideration of the other versions of the QMB for further publications.
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Affiliation(s)
- Daniel K Wójcik
- Institute for Physical Science and Technology, University of Maryland, College Park 20742, USA.
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38
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Dorfman JR, Gaspard P, Gilbert T. Entropy production of diffusion in spatially periodic deterministic systems. Phys Rev E Stat Nonlin Soft Matter Phys 2002; 66:026110. [PMID: 12241240 DOI: 10.1103/physreve.66.026110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2002] [Indexed: 05/23/2023]
Abstract
This paper presents an ab initio derivation of the expression given by irreversible thermodynamics for the rate of entropy production for different classes of diffusive processes. The first class is Lorentz gases, where noninteracting particles move on a spatially periodic lattice, and collide elastically with fixed scatterers. The second class is periodic systems, where N particles interact with each other, and one of them is a tracer particle that diffuses among the cells of the lattice. We assume that, in either case, the dynamics of the system are deterministic and hyperbolic, with positive Lyapunov exponents. This work extends methods originally developed for a chaotic two-dimensional model of diffusion, the multi-baker map, to higher-dimensional, continuous-time dynamical systems appropriate for systems with one or more moving particles. Here we express the rate of entropy production in terms of hydrodynamic measures that are determined by the fractal properties of microscopic hydrodynamic modes that describe the slowest decay of the system to an equilibrium state.
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Affiliation(s)
- J R Dorfman
- Department of Physics and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA.
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39
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Abstract
The differentiation and survival of developing alpha beta thymocytes depends on effective T-cell receptor (TCR) signaling upon recognition of self peptide/major histocompatibility complex (MHC) molecule ligands. Although this concept is uniformly accepted with regard to immature thymocytes, there are conflicting reports as to whether or not MHC recognition is required for survival of mature peripheral naïve T cells. In this review, we assess these reports critically and conclude that in many cases, the differences observed in CD4(+) T-cell recovery between MHC-expressing and MHC-deficient animals can be attributed to proliferation occurring only in the MHC-expressing lymphopenic animals studied in these models systems, rather than to effects of MHC recognition on cell viability per se. Still other reports involve experimental manipulations that may have affected the intrathymic development of the T cells such that they receive a "poor" selecting signal, fail to fully mature, and thus behave more like thymocytes in their survival characteristics (i.e., show MHC dependence). With respect to CD8(+) T cells, we discuss data suggesting that some clones are more dependent upon the presence of MHC class I for survival than others. We propose that some CD8(+) T cells even in a wild-type host may behave like the manipulated CD4(+) T cells just described, and fail to mature completely with respect to their survival requirements. Although the proportion of CD8(+) cells in this MHC-dependent state is not known, the corresponding fraction among CD4(+) T cells seems to be rather small. Overall, our analysis of the available data suggests that most or all mature CD4(+) (and perhaps also many CD8(+)) T lymphocytes do not depend on self-recognition for their viability in the periphery.
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Affiliation(s)
- Jeffrey R Dorfman
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bldg. 10 Rm. 11N311, 10 Center Dr. MSC-1892, National Institutes of Health, Bethesda, MD 20892, USA
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40
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Dellago C, Beijeren H, Panja D, Dorfman JR. Field-dependent collision frequency of the two-dimensional driven random Lorentz gas. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:036217. [PMID: 11580432 DOI: 10.1103/physreve.64.036217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2001] [Indexed: 05/23/2023]
Abstract
In the field-driven, thermostated Lorentz gas the collision frequency increases with the magnitude of the applied field due to long-time correlations. We study this effect with computer simulations and confirm the presence of nonanalytic terms in the field dependence of the collision rate as predicted by kinetic theory.
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Affiliation(s)
- C Dellago
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
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41
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Abstract
Transport by normal diffusion can be decomposed into hydrodynamic modes which relax exponentially toward the equilibrium state. In chaotic systems with 2 degrees of freedom, the fine scale structures of these modes are singular and fractal, characterized by a Hausdorff dimension given in terms of Ruelle's topological pressure. For long-wavelength modes, we relate the Hausdorff dimension to the diffusion coefficient and the Lyapunov exponent. This relationship is tested numerically on two Lorentz gases, one with hard repulsive forces, the other with attractive, Yukawa forces. The agreement with theory is excellent.
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Affiliation(s)
- P Gaspard
- Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, Code Postal 231, Campus Plaine, B-1050 Brussels, Belgium
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42
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Affiliation(s)
- Jeffrey R. Dorfman
- Lymphocyte Biology Section, Laboratory of Immunology, Building 10 Room 11N311, National Institutes of Health, Bethesda, MD 20892-1892, USA.
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43
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van Beijeren H, Latz A, Dorfman JR. Chaotic properties of dilute two- and three-dimensional random Lorentz gases. II. Open systems. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 63:016312. [PMID: 11304358 DOI: 10.1103/physreve.63.016312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2000] [Indexed: 05/23/2023]
Abstract
We calculate the spectrum of Lyapunov exponents for a point particle moving in a random array of fixed hard disk or hard sphere scatterers, i.e., the disordered Lorentz gas, in a generic nonequilibrium situation. In a large system which is finite in at least some directions, and with absorbing boundary conditions, the moving particle escapes the system with probability one. However, there is a set of zero Lebesgue measure of initial phase points for the moving particle, such that escape never occurs. Typically, this set of points forms a fractal repeller, and the Lyapunov spectrum is calculated here for trajectories on this repeller. For this calculation, we need the solution of the recently introduced extended Boltzmann equation for the nonequilibrium distribution of the radius of curvature matrix and the solution of the standard Boltzmann equation. The escape-rate formalism then gives an explicit result for the Kolmogorov Sinai entropy on the repeller.
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Affiliation(s)
- H van Beijeren
- Institute for Theoretical Physics, University of Utrecht, Postbus 80006, Utrecht 3508 TA, The Netherlands
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44
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Abstract
T cell receptor (TCR) signaling triggered by recognition of self-major histocompatibility complex (MHC) ligands has been proposed to maintain the viability of naïve T cells and to provoke their proliferation in T cell-deficient hosts. Consistent with this, the partially phosphorylated state of TCR zeta chains in naïve CD4+ and CD8+ T cells in vivo was found to be actively maintained by TCR interactions with specific peptide-containing MHC molecules. TCR ligand-dependent phosphorylation of TCR zeta was lost within one day of cell transfer into MHC-deficient hosts, yet the survival of transferred CD4+ lymphocytes was the same in recipients with or without MHC class II expression for one month. Thus, despite clear evidence for TCR signaling in nonactivated naïve T cells, these data argue against the concept that such signaling plays a predominant role in determining lymphocyte lifespan.
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Affiliation(s)
- J R Dorfman
- Lymphocyte Biology Section, Laboratory of Immunology, Building 10 Room 11N311, National Institutes of Health, Bethesda, MD 20892, USA
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45
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Abstract
The theory of entropy production in nonequilibrium, Hamiltonian systems, previously described for steady states using partitions of phase space, is here extended to time dependent systems relaxing to equilibrium. We illustrate the main ideas by using a simple multibaker model, with some nonequilibrium initial state, and we study its progress toward equilibrium. The central results are (i) the entropy production is governed by an underlying, exponentially decaying fractal structure in phase space, (ii) the rate of entropy production is largely independent of the scale of resolution used in the partitions, and (iii) the rate of entropy production is in agreement with the predictions of nonequilibrium thermodynamics.
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Affiliation(s)
- T Gilbert
- Department of Physics and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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46
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Klages R, Dorfman JR. Simple deterministic dynamical systems with fractal diffusion coefficients. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1999; 59:5361-83. [PMID: 11969496 DOI: 10.1103/physreve.59.5361] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/1998] [Revised: 01/11/1999] [Indexed: 04/18/2023]
Abstract
We analyze a simple model of deterministic diffusion. The model consists of a one-dimensional array of scatterers with moving point particles. The particles move from one scatterer to the next according to a piecewise linear, expanding, deterministic map on unit intervals. The microscopic chaotic scattering process of the map can be changed by a control parameter. The macroscopic diffusion coefficient for the moving particles is well defined and depends upon the control parameter. We calculate the diffusion coefficent and the largest eigenmodes of the system by using Markov partitions and by solving the eigenvalue problems of respective topological transition matrices. For different boundary conditions we find that the largest eigenmodes of the map match the ones of the simple phenomenological diffusion equation. Our main result is that the diffusion coefficient exhibits a fractal structure as a function of the control parameter. We provide qualitative and quantitative arguments to explain features of this fractal structure.
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Affiliation(s)
- R Klages
- Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstrasse 36, D-10623 Berlin, Germany.
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47
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Abstract
The formation of the repertoire of mouse natural killer (NK) cell receptors for major histocompatibility complex (MHC) class I molecules was investigated by determining the developmental pattern of Ly49 receptor expression. During the first days after birth, few or no splenic NK cells express Ly49A, Ly49C, Ly49G2, or Ly49I receptors. The proportion of Ly49+ splenic NK cells gradually rises to adult levels during the first 6-8 wk of life. The appearance of appreciable numbers of splenic Ly49+ NK cells coincides with the appearance of NK activity at 3-4 wk. After in vivo transfer, NK cells not expressing specific Ly49 receptors can give rise to NK cells that do, and cells expressing one of these four Ly49 receptors can give rise to cells expressing others. Once initiated, expression of a Ly49 receptor is stable for at least 10 d after in vivo transfer. Hence, initiation of Ly49 receptor expression occurs successively. Interestingly, expression of one of the receptors tested, Ly49A, did not occur after in vivo transfer of Ly49A- cells. One possible explanation for these data is that the order of Ly49 receptor expression by NK cells is nonrandom. The results provide a framework for evaluating models of NK cell repertoire formation, and how the repertoire is molded by host class I MHC molecules.
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MESH Headings
- Animals
- Antigens/biosynthesis
- Antigens, Ly
- Antigens, Surface/biosynthesis
- Cell Differentiation
- Cells, Cultured
- Gene Expression Regulation, Developmental
- Killer Cells, Natural/cytology
- Killer Cells, Natural/metabolism
- Lectins, C-Type
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/genetics
- Mice
- Mice, Inbred C57BL
- NK Cell Lectin-Like Receptor Subfamily A
- NK Cell Lectin-Like Receptor Subfamily B
- Protein Biosynthesis
- Proteins
- Receptors, Immunologic/biosynthesis
- Receptors, NK Cell Lectin-Like
- Spleen/cytology
- Spleen/embryology
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Affiliation(s)
- J R Dorfman
- Department of Molecular and Cell Biology and the Cancer Research Laboratory, University of California at Berkeley, Berkeley, California 94720, USA
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48
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Dorfman JR, Zerrahn J, Coles MC, Raulet DH. The basis for self-tolerance of natural killer cells in beta2-microglobulin- and TAP-1- mice. The Journal of Immunology 1997. [DOI: 10.4049/jimmunol.159.11.5219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Cells from mice with mutations in the genes for beta2-microglobulin (beta2m) or for TAP-1 express only low levels of MHC class I proteins on their surfaces, and are thus sensitive to attack by normal NK cells. Although NK cells are present in beta2m- mice and TAP-1(-) mice, they are completely self-tolerant. The underlying mechanism for this tolerance is unknown. It has been proposed that education processes render NK cells from these mice hypersensitive to class I-mediated inhibition, so that they can be inhibited even by the low levels of class I expressed on autologous cells. In this study, we present evidence against this hypothesis, by demonstrating that NK cells from beta2m- mice and TAP-1(-) mice fail to attack beta2m(-)TAP-1(-) double-mutant cells in both in vitro and in vivo assays. The latter cells express substantially lower levels of class I than single-mutant cells, based on serologic tests, as well as a significantly diminished sensitivity to attack by class I-specific CTL. Furthermore, the Ly-49 repertoire on NK cells derived from beta2m(-)TAP-1(-) mice is highly similar to that of either single mutant, indicating that the developmental processes that shape the Ly-49 repertoire cannot respond to the differences in class I levels among these mice. We propose that self-tolerance of NK cells in beta2m- mice and TAP-1(-) mice is likely to result from hyporesponsiveness of the cells to activating signals, or alternatively, to induction of inhibitory signaling through receptors specific for non-class I MHC ligands.
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Affiliation(s)
- J R Dorfman
- Department of Molecular and Cell Biology & Cancer Research Laboratory, University of California at Berkeley, 94720, USA
| | - J Zerrahn
- Department of Molecular and Cell Biology & Cancer Research Laboratory, University of California at Berkeley, 94720, USA
| | - M C Coles
- Department of Molecular and Cell Biology & Cancer Research Laboratory, University of California at Berkeley, 94720, USA
| | - D H Raulet
- Department of Molecular and Cell Biology & Cancer Research Laboratory, University of California at Berkeley, 94720, USA
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49
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Dorfman JR, Zerrahn J, Coles MC, Raulet DH. The basis for self-tolerance of natural killer cells in beta2-microglobulin- and TAP-1- mice. J Immunol 1997; 159:5219-25. [PMID: 9548460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cells from mice with mutations in the genes for beta2-microglobulin (beta2m) or for TAP-1 express only low levels of MHC class I proteins on their surfaces, and are thus sensitive to attack by normal NK cells. Although NK cells are present in beta2m- mice and TAP-1(-) mice, they are completely self-tolerant. The underlying mechanism for this tolerance is unknown. It has been proposed that education processes render NK cells from these mice hypersensitive to class I-mediated inhibition, so that they can be inhibited even by the low levels of class I expressed on autologous cells. In this study, we present evidence against this hypothesis, by demonstrating that NK cells from beta2m- mice and TAP-1(-) mice fail to attack beta2m(-)TAP-1(-) double-mutant cells in both in vitro and in vivo assays. The latter cells express substantially lower levels of class I than single-mutant cells, based on serologic tests, as well as a significantly diminished sensitivity to attack by class I-specific CTL. Furthermore, the Ly-49 repertoire on NK cells derived from beta2m(-)TAP-1(-) mice is highly similar to that of either single mutant, indicating that the developmental processes that shape the Ly-49 repertoire cannot respond to the differences in class I levels among these mice. We propose that self-tolerance of NK cells in beta2m- mice and TAP-1(-) mice is likely to result from hyporesponsiveness of the cells to activating signals, or alternatively, to induction of inhibitory signaling through receptors specific for non-class I MHC ligands.
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Affiliation(s)
- J R Dorfman
- Department of Molecular and Cell Biology & Cancer Research Laboratory, University of California at Berkeley, 94720, USA
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50
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Raulet DH, Held W, Correa I, Dorfman JR, Wu MF, Corral L. Specificity, tolerance and developmental regulation of natural killer cells defined by expression of class I-specific Ly49 receptors. Immunol Rev 1997; 155:41-52. [PMID: 9059881 DOI: 10.1111/j.1600-065x.1997.tb00938.x] [Citation(s) in RCA: 185] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Natural killer cells in the mouse express class I MHC-specific inhibitory receptors of the Ly49 protein family. The receptors mediate inhibition of the lysis of tumor cells and normal cells, and mediate the specificity of bone-marrow graft rejection by NK cells in vivo. The function of these receptors may be to confer upon NK cells the capacity to distinguish normal self cells from cells that have down-regulated expression of some or all self-class I molecules. Ly49 receptors discriminate between different class I molecules, and are distributed in expression to overlapping subsets of NK cells. The receptors appear to interact with class I-MHC residues and associated N-glycans, with little or no discrimination of the class I-bound peptide. The Ly49 receptor repertoire may be initially generated by a stochastic process that distributes receptors randomly to different cells and treats the two alleles of a given Ly49 gene independently. However, class I-MHC-dependent "education" processes shape the functional repertoire. The education processes silence potentially auto-aggressive NK cells, probably by ensuring that each NK cell expresses at least one self-specific Ly49 receptor. In addition, NK cell clones that express multiple self-specific Ly49 receptors are disfavored by the education processes, perhaps to confer greater discrimination on to individual NK cells.
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Affiliation(s)
- D H Raulet
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA.
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