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Hu L, Zhao B, Liu M, Gao Y, Ding H, Hu Q, An M, Shang H, Han X. Optimization of genetic distance threshold for inferring the CRF01_AE molecular network based on next-generation sequencing. Front Cell Infect Microbiol 2024; 14:1388059. [PMID: 38846352 PMCID: PMC11155296 DOI: 10.3389/fcimb.2024.1388059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 03/28/2024] [Indexed: 06/09/2024] Open
Abstract
Introduction HIV molecular network based on genetic distance (GD) has been extensively utilized. However, the GD threshold for the non-B subtype differs from that of subtype B. This study aimed to optimize the GD threshold for inferring the CRF01_AE molecular network. Methods Next-generation sequencing data of partial CRF01_AE pol sequences were obtained for 59 samples from 12 transmission pairs enrolled from a high-risk cohort during 2009 and 2014. The paired GD was calculated using the Tamura-Nei 93 model to infer a GD threshold range for HIV molecular networks. Results 2,019 CRF01_AE pol sequences and information on recent HIV infection (RHI) from newly diagnosed individuals in Shenyang from 2016 to 2019 were collected to construct molecular networks to assess the ability of the inferred GD thresholds to predict recent transmission events. When HIV transmission occurs within a span of 1-4 years, the mean paired GD between the sequences of the donor and recipient within the same transmission pair were as follow: 0.008, 0.011, 0.013, and 0.023 substitutions/site. Using these four GD thresholds, it was found that 98.9%, 96.0%, 88.2%, and 40.4% of all randomly paired GD values from 12 transmission pairs were correctly identified as originating from the same transmission pairs. In the real world, as the GD threshold increased from 0.001 to 0.02 substitutions/site, the proportion of RHI within the molecular network gradually increased from 16.6% to 92.3%. Meanwhile, the proportion of links with RHI gradually decreased from 87.0% to 48.2%. The two curves intersected at a GD of 0.008 substitutions/site. Discussion A suitable range of GD thresholds, 0.008-0.013 substitutions/site, was identified to infer the CRF01_AE molecular transmission network and identify HIV transmission events that occurred within the past three years. This finding provides valuable data for selecting an appropriate GD thresholds in constructing molecular networks for non-B subtypes.
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Affiliation(s)
- Lijuan Hu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Key Laboratory of AIDS Immunology of Liaoning Province, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Bin Zhao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Key Laboratory of AIDS Immunology of Liaoning Province, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Mingchen Liu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Yang Gao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Haibo Ding
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Key Laboratory of AIDS Immunology of Liaoning Province, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Qinghai Hu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Key Laboratory of AIDS Immunology of Liaoning Province, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Minghui An
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Key Laboratory of AIDS Immunology of Liaoning Province, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Hong Shang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Key Laboratory of AIDS Immunology of Liaoning Province, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xiaoxu Han
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- National Health Commission (NHC) Key Laboratory of AIDS Prevention and Treatment, National Clinical Research Center for Laboratory Medicine, The First Hospital of China Medical University, China Medical University, Shenyang, China
- Laboratory Medicine Innovation Unit, Chinese Academy of Medical Sciences, Shenyang, China
- Key Laboratory of AIDS Immunology of Liaoning Province, Shenyang, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
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Alizon S. Multiple infection theory rather than 'socio-virology'? A commentary on Leeks et al. 2023. J Evol Biol 2023; 36:1571-1576. [PMID: 37975504 DOI: 10.1111/jeb.14245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 11/19/2023]
Affiliation(s)
- Samuel Alizon
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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3
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Lundgren E, Romero-Severson E, Albert J, Leitner T. Combining biomarker and virus phylogenetic models improves HIV-1 epidemiological source identification. PLoS Comput Biol 2022; 18:e1009741. [PMID: 36026480 PMCID: PMC9455879 DOI: 10.1371/journal.pcbi.1009741] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 09/08/2022] [Accepted: 08/02/2022] [Indexed: 01/07/2023] Open
Abstract
To identify and stop active HIV transmission chains new epidemiological techniques are needed. Here, we describe the development of a multi-biomarker augmentation to phylogenetic inference of the underlying transmission history in a local population. HIV biomarkers are measurable biological quantities that have some relationship to the amount of time someone has been infected with HIV. To train our model, we used five biomarkers based on real data from serological assays, HIV sequence data, and target cell counts in longitudinally followed, untreated patients with known infection times. The biomarkers were modeled with a mixed effects framework to allow for patient specific variation and general trends, and fit to patient data using Markov Chain Monte Carlo (MCMC) methods. Subsequently, the density of the unobserved infection time conditional on observed biomarkers were obtained by integrating out the random effects from the model fit. This probabilistic information about infection times was incorporated into the likelihood function for the transmission history and phylogenetic tree reconstruction, informed by the HIV sequence data. To critically test our methodology, we developed a coalescent-based simulation framework that generates phylogenies and biomarkers given a specific or general transmission history. Testing on many epidemiological scenarios showed that biomarker augmented phylogenetics can reach 90% accuracy under idealized situations. Under realistic within-host HIV-1 evolution, involving substantial within-host diversification and frequent transmission of multiple lineages, the average accuracy was at about 50% in transmission clusters involving 5-50 hosts. Realistic biomarker data added on average 16 percentage points over using the phylogeny alone. Using more biomarkers improved the performance. Shorter temporal spacing between transmission events and increased transmission heterogeneity reduced reconstruction accuracy, but larger clusters were not harder to get right. More sequence data per infected host also improved accuracy. We show that the method is robust to incomplete sampling and that adding biomarkers improves reconstructions of real HIV-1 transmission histories. The technology presented here could allow for better prevention programs by providing data for locally informed and tailored strategies.
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Affiliation(s)
- Erik Lundgren
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Ethan Romero-Severson
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Jan Albert
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Thomas Leitner
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- * E-mail:
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4
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Elie B, Selinger C, Alizon S. The source of individual heterogeneity shapes infectious disease outbreaks. Proc Biol Sci 2022; 289:20220232. [PMID: 35506229 PMCID: PMC9065969 DOI: 10.1098/rspb.2022.0232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
There is known heterogeneity between individuals in infectious disease transmission patterns. The source of this heterogeneity is thought to affect epidemiological dynamics but studies tend not to control for the overall heterogeneity in the number of secondary cases caused by an infection. To explore the role of individual variation in infection duration and transmission rate in parasite emergence and spread, while controlling for this potential bias, we simulate stochastic outbreaks with and without parasite evolution. As expected, heterogeneity in the number of secondary cases decreases the probability of outbreak emergence. Furthermore, for epidemics that do emerge, assuming more realistic infection duration distributions leads to faster outbreaks and higher epidemic peaks. When parasites require adaptive mutations to cause large epidemics, the impact of heterogeneity depends on the underlying evolutionary model. If emergence relies on within-host evolution, decreasing the infection duration variance decreases the probability of emergence. These results underline the importance of accounting for realistic distributions of transmission rates to anticipate the effect of individual heterogeneity on epidemiological dynamics.
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Affiliation(s)
- Baptiste Elie
- MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France
| | - Christian Selinger
- MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France.,Swiss Tropical and Public Health Institute, Basel, Kreuzstrasse 2, Allschwil 4123, Switzerland
| | - Samuel Alizon
- MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France.,Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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5
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Abstract
HIV is one of the fastest evolving organisms known. It evolves about 1 million times faster than its host, humans. Because HIV establishes chronic infections, with continuous evolution, its divergence within a single infected human surpasses the divergence of the entire humanoid history. Yet, it is still the same virus, infecting the same cell types and using the same replication machinery year after year. Hence, one would think that most mutations that HIV accumulates are neutral. But the picture is more complicated than that. HIV evolution is also a clear example of strong positive selection, that is, mutants have a survival advantage. How do these facts come together?
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Affiliation(s)
- Thomas Leitner
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM
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6
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Potential immune escape mutations under inferred selection pressure in HIV-1 strains circulating in Medellín, Colombia. INFECTION GENETICS AND EVOLUTION 2018; 69:267-278. [PMID: 30808498 DOI: 10.1016/j.meegid.2018.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/22/2018] [Accepted: 07/02/2018] [Indexed: 11/20/2022]
Abstract
The introduction of highly active antiretroviral therapy (HAART) has significantly improved life expectancy of HIV-infected patients; nevertheless, it does not eliminate the virus from hosts, so a cure for this infection is crucial. Some strategies have employed the induction of anti-HIV CD8+ T cells. However, the high genetic variability of HIV-1 represents the biggest obstacle for these strategies, since immune escape mutations within epitopes restricted by Human Leukocyte Antigen class I molecules (HLA-I) abrogate the antiviral activity of these cells. We used a bioinformatics pipeline for the determination of such mutations, based on selection pressure and docking/refinement analyses. Fifty HIV-1 infected patients were recruited; HLA-A and HLA-B alleles were typified using sequence-specific oligonucleotide approach, and viral RNA was extracted for the amplification of HIV-1 gag, which was bulk sequenced and aligned to perform selection pressure analysis, using Single Likelihood Ancestor Counting (SLAC) and Fast Unconstrained Bayesian Approximation (FUBAR) algorithms. Positively selected sites were mapped into HLA-I-specific epitopes, and both mutated and wild type epitopes were modelled using PEP-FOLD. Molecular docking and refinement assays were carried out using AutoDock Vina 4 and FlexPepDock. Five positively selected sites were found: S54 at HLA-A*02 GC9, T84 at HLA-A*02 SL9, S125 at HLA-B*35 HY9, S173 at HLA-A*02/B*57 KS12 and I223 at HLA-B*35 HA9. Although some mutations have been previously described as immune escape mutations, the majority of them have not been reported. Molecular docking/refinement analysis showed that one combination of mutations at GC9, one at SL9, and eight at HY9 epitopes could act as immune escape mutations. Moreover, HLA-A*02-positive patients harbouring mutations at KS12, and HLA-B*35-positive patients with mutations at HY9 have significantly higher plasma viral loads than patients lacking such mutations. Thus, HLA-A and -B alleles could be shaping the genetic diversity of HIV-1 through the selection of potential immune escape mutations.
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Abstract
The evolution of viral pathogens is shaped by strong selective forces that are exerted during jumps to new hosts, confrontations with host immune responses and antiviral drugs, and numerous other processes. However, while undeniably strong and frequent, adaptive evolution is largely confined to small parts of information-packed viral genomes, and the majority of observed variation is effectively neutral. The predictions and implications of the neutral theory have proven immensely useful in this context, with applications spanning understanding within-host population structure, tracing the origins and spread of viral pathogens, predicting evolutionary dynamics, and modeling the emergence of drug resistance. We highlight the multiple ways in which the neutral theory has had an impact, which has been accelerated in the age of high-throughput, high-resolution genomics.
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Affiliation(s)
- Simon D W Frost
- Department of Veterinary Medicine, University of Cambridge, Cambridge,
United Kingdom
- The Alan Turing Institute, London, United Kingdom
| | - Brittany Rife Magalis
- Institute for Genomics and Evolutionary Medicine, Temple University,
Philadelphia, PA
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8
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Cissé OH, Ma L, Wei Huang D, Khil PP, Dekker JP, Kutty G, Bishop L, Liu Y, Deng X, Hauser PM, Pagni M, Hirsch V, Lempicki RA, Stajich JE, Cuomo CA, Kovacs JA. Comparative Population Genomics Analysis of the Mammalian Fungal Pathogen Pneumocystis. mBio 2018; 9:e00381-18. [PMID: 29739910 PMCID: PMC5941068 DOI: 10.1128/mbio.00381-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/19/2018] [Indexed: 01/14/2023] Open
Abstract
Pneumocystis species are opportunistic mammalian pathogens that cause severe pneumonia in immunocompromised individuals. These fungi are highly host specific and uncultivable in vitro Human Pneumocystis infections present major challenges because of a limited therapeutic arsenal and the rise of drug resistance. To investigate the diversity and demographic history of natural populations of Pneumocystis infecting humans, rats, and mice, we performed whole-genome and large-scale multilocus sequencing of infected tissues collected in various geographic locations. Here, we detected reduced levels of recombination and variations in historical demography, which shape the global population structures. We report estimates of evolutionary rates, levels of genetic diversity, and population sizes. Molecular clock estimates indicate that Pneumocystis species diverged before their hosts, while the asynchronous timing of population declines suggests host shifts. Our results have uncovered complex patterns of genetic variation influenced by multiple factors that shaped the adaptation of Pneumocystis populations during their spread across mammals.IMPORTANCE Understanding how natural pathogen populations evolve and identifying the determinants of genetic variation are central issues in evolutionary biology. Pneumocystis, a fungal pathogen which infects mammals exclusively, provides opportunities to explore these issues. In humans, Pneumocystis can cause a life-threatening pneumonia in immunosuppressed individuals. In analysis of different Pneumocystis species infecting humans, rats, and mice, we found that there are high infection rates and that natural populations maintain a high level of genetic variation despite low levels of recombination. We found no evidence of population structuring by geography. Our comparisons of the times of divergence of these species to their respective hosts suggest that Pneumocystis may have undergone recent host shifts. The results demonstrate that Pneumocystis strains are widely disseminated geographically and provide a new understanding of the evolution of these pathogens.
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Affiliation(s)
- Ousmane H Cissé
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Liang Ma
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Da Wei Huang
- Lymphoid Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Pavel P Khil
- Department of Laboratory Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - John P Dekker
- Department of Laboratory Medicine, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Geetha Kutty
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Lisa Bishop
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Yueqin Liu
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Xilong Deng
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Vanessa Hirsch
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, USA
| | - Richard A Lempicki
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Jason E Stajich
- Department of Plant Pathology and Microbiology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, USA
| | - Christina A Cuomo
- Infectious Disease and Microbiome Program, Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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9
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Arenas M, Araujo NM, Branco C, Castelhano N, Castro-Nallar E, Pérez-Losada M. Mutation and recombination in pathogen evolution: Relevance, methods and controversies. INFECTION GENETICS AND EVOLUTION 2017; 63:295-306. [PMID: 28951202 DOI: 10.1016/j.meegid.2017.09.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
Abstract
Mutation and recombination drive the evolution of most pathogens by generating the genetic variants upon which selection operates. Those variants can, for example, confer resistance to host immune systems and drug therapies or lead to epidemic outbreaks. Given their importance, diverse evolutionary studies have investigated the abundance and consequences of mutation and recombination in pathogen populations. However, some controversies persist regarding the contribution of each evolutionary force to the development of particular phenotypic observations (e.g., drug resistance). In this study, we revise the importance of mutation and recombination in the evolution of pathogens at both intra-host and inter-host levels. We also describe state-of-the-art analytical methodologies to detect and quantify these two evolutionary forces, including biases that are often ignored in evolutionary studies. Finally, we present some of our former studies involving pathogenic taxa where mutation and recombination played crucial roles in the recovery of pathogenic fitness, the generation of interspecific genetic diversity, or the design of centralized vaccines. This review also illustrates several common controversies and pitfalls in the analysis and in the evaluation and interpretation of mutation and recombination outcomes.
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Affiliation(s)
- Miguel Arenas
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo, Spain; Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Natalia M Araujo
- Laboratory of Molecular Virology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.
| | - Catarina Branco
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Nadine Castelhano
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Eduardo Castro-Nallar
- Universidad Andrés Bello, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias Biológicas, Santiago, Chile.
| | - Marcos Pérez-Losada
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Ashburn, VA 20147, Washington, DC, United States; CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão 4485-661, Portugal.
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10
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Hedegaard DL, Tully DC, Rowe IA, Reynolds GM, Bean DJ, Hu K, Davis C, Wilhelm A, Ogilvie CB, Power KA, Tarr AW, Kelly D, Allen TM, Balfe P, McKeating JA. High resolution sequencing of hepatitis C virus reveals limited intra-hepatic compartmentalization in end-stage liver disease. J Hepatol 2017; 66:28-38. [PMID: 27531641 PMCID: PMC5558612 DOI: 10.1016/j.jhep.2016.07.048] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/22/2016] [Accepted: 07/29/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS The high replication and mutation rate of hepatitis C virus (HCV) results in a heterogeneous population of viral sequences in vivo. HCV replicates in the liver and infected hepatocytes occur as foci surrounded by uninfected cells that may promote compartmentalization of viral variants. Given recent reports showing interferon stimulated gene (ISG) expression in chronic hepatitis C, we hypothesized that local interferon responses may limit HCV replication and evolution. METHODS To investigate the spatial influence of liver architecture on viral replication we measured HCV RNA and ISG mRNA from each of the 8 Couinaud segments of the liver from 21 patients undergoing liver transplant. RESULTS HCV RNA and ISG mRNA levels were comparable across all sites from an individual liver but showed up to 500-fold difference between patients. Importantly, there was no association between ISG and HCV RNA expression across all sites in the liver or plasma. Deep sequencing of HCV RNA isolated from the 8 hepatic sites from two subjects showed a similar distribution of viral quasispecies across the liver and uniform sequence diversity. Single genome amplification of HCV E1E2-envelope clones from 6 selected patients at 2 hepatic sites supported these data and showed no evidence for HCV compartmentalization. CONCLUSIONS We found no differences between the hepatic and plasma viral quasispecies in all patients sampled. We conclude that in end-stage liver disease HCV RNA levels and the genetic pool of HCV envelope sequences are indistinguishable between distant sites in the liver and plasma, arguing against viral compartmentalization. LAY SUMMARY HCV is an RNA virus that exists as a quasispecies of closely related genomes that are under continuous selection by host innate and adaptive immune responses and antiviral drug therapy. The primary site of HCV replication is the liver and yet our understanding of the spatial distribution of viral variants within the liver is limited. High resolution sequencing of HCV and monitoring of innate immune responses at multiple sites across the liver identified a uniform pattern of diversity and argues against viral compartmentalization.
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Affiliation(s)
| | | | - Ian A. Rowe
- Centre for Human Virology, University of Birmingham, Birmingham, UK
| | - Gary M. Reynolds
- NIHR Birmingham Liver Biomedical Research Unit, University of Birmingham, UK
| | - David J. Bean
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Ke Hu
- Centre for Human Virology, University of Birmingham, Birmingham, UK
| | | | - Annika Wilhelm
- NIHR Birmingham Liver Biomedical Research Unit, University of Birmingham, UK
| | | | - Karen A. Power
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Alexander W. Tarr
- School of Life Sciences, Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, UK
| | - Deirdre Kelly
- Liver Unit, Birmingham Childrens’ Hospital, Birmingham, UK
| | - Todd M. Allen
- Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA
| | - Peter Balfe
- Centre for Human Virology, University of Birmingham, Birmingham, UK.
| | - Jane A. McKeating
- Centre for Human Virology, University of Birmingham, Birmingham, UK,NIHR Birmingham Liver Biomedical Research Unit, University of Birmingham, UK,Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2a, D-85748 Garching, Germany
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11
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Feder AF, Rhee SY, Holmes SP, Shafer RW, Petrov DA, Pennings PS. More effective drugs lead to harder selective sweeps in the evolution of drug resistance in HIV-1. eLife 2016; 5. [PMID: 26882502 PMCID: PMC4764592 DOI: 10.7554/elife.10670] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 01/18/2016] [Indexed: 01/28/2023] Open
Abstract
In the early days of HIV treatment, drug resistance occurred rapidly and predictably in all patients, but under modern treatments, resistance arises slowly, if at all. The probability of resistance should be controlled by the rate of generation of resistance mutations. If many adaptive mutations arise simultaneously, then adaptation proceeds by soft selective sweeps in which multiple adaptive mutations spread concomitantly, but if adaptive mutations occur rarely in the population, then a single adaptive mutation should spread alone in a hard selective sweep. Here, we use 6717 HIV-1 consensus sequences from patients treated with first-line therapies between 1989 and 2013 to confirm that the transition from fast to slow evolution of drug resistance was indeed accompanied with the expected transition from soft to hard selective sweeps. This suggests more generally that evolution proceeds via hard sweeps if resistance is unlikely and via soft sweeps if it is likely. DOI:http://dx.doi.org/10.7554/eLife.10670.001 In the early days of HIV therapy, the strains of the virus that infected patients frequently evolved drug resistance and the therapies would often eventually fail. These treatments generally involved using a single anti-viral drug. Nowadays, better therapies involving combinations of several anti-viral drugs are available and drug resistance in HIV is a much rarer occurrence. This means that now a particular therapy may be an effective treatment for an HIV-infected individual over much longer periods of time. A theory of population genetics predicts that when it is easy for a population to acquire a beneficial genetic mutation – like one that provides drug resistance – multiple versions of that mutation may spread in the population at the same time. This is called a soft selective sweep. However, when beneficial mutations occur only rarely, it is expected that only one version of that mutation will take over in a population, which is known as a hard selective sweep. Here, Feder et al. test this theory using data from 6717 patients with HIV who were treated between 1989 and 2013 using a variety of different drug therapies. The experiments aimed to find out whether the transition from the older drug therapies –where the virus frequently acquired resistance – to the newer, more effective drugs was associated with a transition from soft to hard sweeps. Feder et al. find that HIV more often evolved drug resistance via soft sweeps in patients treated with the less effective drug combinations (like those given in the early days of HIV treatment), while hard sweeps were more common with the more effective drug combinations. This suggests that good drug combinations may allow fewer drug resistance mutations to occur in the HIV population within a patient. This may be because there are fewer virus particles in these patients, or because the specific combinations of mutations that provide resistance occur less often. Feder et al.’s findings are a step towards understanding why modern HIV treatments work so well, which will ultimately help us find better treatments for other infectious diseases. DOI:http://dx.doi.org/10.7554/eLife.10670.002
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Affiliation(s)
- Alison F Feder
- Department of Biology, Stanford University, Stanford, United States
| | - Soo-Yon Rhee
- Department of Medicine, Stanford University, Stanford, United States
| | - Susan P Holmes
- Department of Statistics, Stanford University, Stanford, United States
| | - Robert W Shafer
- Department of Medicine, Stanford University, Stanford, United States
| | - Dmitri A Petrov
- Department of Biology, Stanford University, Stanford, United States
| | - Pleuni S Pennings
- Department of Biology, Stanford University, Stanford, United States.,Department of Biology, San Francisco State University, San Francisco, United States
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Longitudinal Antigenic Sequences and Sites from Intra-Host Evolution (LASSIE) Identifies Immune-Selected HIV Variants. Viruses 2015; 7:5443-75. [PMID: 26506369 PMCID: PMC4632389 DOI: 10.3390/v7102881] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023] Open
Abstract
Within-host genetic sequencing from samples collected over time provides a dynamic view of how viruses evade host immunity. Immune-driven mutations might stimulate neutralization breadth by selecting antibodies adapted to cycles of immune escape that generate within-subject epitope diversity. Comprehensive identification of immune-escape mutations is experimentally and computationally challenging. With current technology, many more viral sequences can readily be obtained than can be tested for binding and neutralization, making down-selection necessary. Typically, this is done manually, by picking variants that represent different time-points and branches on a phylogenetic tree. Such strategies are likely to miss many relevant mutations and combinations of mutations, and to be redundant for other mutations. Longitudinal Antigenic Sequences and Sites from Intrahost Evolution (LASSIE) uses transmitted founder loss to identify virus "hot-spots" under putative immune selection and chooses sequences that represent recurrent mutations in selected sites. LASSIE favors earliest sequences in which mutations arise. With well-characterized longitudinal Env sequences, we confirmed selected sites were concentrated in antibody contacts and selected sequences represented diverse antigenic phenotypes. Practical applications include rapidly identifying immune targets under selective pressure within a subject, selecting minimal sets of reagents for immunological assays that characterize evolving antibody responses, and for immunogens in polyvalent "cocktail" vaccines.
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13
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Global Database-Driven Assessment of HIV-1 Adaptation to the Immune Repertoires of Human Populations. J Virol 2015; 89:10693-5. [PMID: 26246562 DOI: 10.1128/jvi.01355-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/27/2015] [Indexed: 11/20/2022] Open
Abstract
Associations between HIV-1 cytotoxic T lymphocyte (CTL) escape mutations and their restricting human leukocyte antigen (HLA) alleles imply that HIV could adapt to divergent HLA repertoires of human populations globally. Using publicly available databases, we examine the relationship between the frequencies of 19 experimentally validated CTL escape mutations in HIV-1 reverse transcriptase and their restricting HLA alleles in 59 countries. From these extensive data, we find evidence of differential HIV adaptations to human populations at only a limited number of the studied epitope sites.
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14
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Genetic Consequences of Antiviral Therapy on HIV-1. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:395826. [PMID: 26170895 PMCID: PMC4478298 DOI: 10.1155/2015/395826] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 11/21/2022]
Abstract
A variety of enzyme inhibitors have been developed in combating HIV-1, however the fast evolutionary rate of this virus commonly leads to the emergence of resistance mutations that finally allows the mutant virus to survive. This review explores the main genetic consequences of HIV-1 molecular evolution during antiviral therapies, including the viral genetic diversity and molecular adaptation. The role of recombination in the generation of drug resistance is also analyzed. Besides the investigation and discussion of published works, an evolutionary analysis of protease-coding genes collected from patients before and after treatment with different protease inhibitors was included to validate previous studies. Finally, the review discusses the importance of considering genetic consequences of antiviral therapies in models of HIV-1 evolution that could improve current genotypic resistance testing and treatments design.
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15
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Abstract
Host immunity is a major driver of pathogen evolution and thus a major determinant of pathogen diversity. Explanations for pathogen diversity traditionally assume simple interactions between pathogens and the immune system, a view encapsulated by the susceptible-infected-recovered (SIR) model. However, there is growing evidence that the complexity of many host-pathogen interactions is dynamically important. This revised perspective requires broadening the definition of a pathogen's immunological phenotype, or what can be thought of as its immunological niche. After reviewing evidence that interactions between pathogens and host immunity drive much of pathogen evolution, I introduce the concept of a pathogen's immunological phenotype. Models that depart from the SIR paradigm demonstrate the utility of this perspective and show that it is particularly useful in understanding vaccine-induced evolution. This paper highlights questions in immunology, evolution, and ecology that must be answered to advance theories of pathogen diversity.
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Affiliation(s)
- Sarah Cobey
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois
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16
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Shirreff G, Alizon S, Cori A, Günthard HF, Laeyendecker O, van Sighem A, Bezemer D, Fraser C. How effectively can HIV phylogenies be used to measure heritability? EVOLUTION MEDICINE AND PUBLIC HEALTH 2013; 2013:209-24. [PMID: 24481201 PMCID: PMC3850537 DOI: 10.1093/emph/eot019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Background and objectives: The severity of HIV-1 infection, measured by set-point viral load (SPVL), is highly variable between individuals. Its heritability between infections quantifies the control the pathogen genotype has over disease severity. Heritability estimates vary widely between studies, but differences in methods make comparison difficult. Phylogenetic comparative analysis offers measures of phylogenetic signal, but it is unclear how to interpret them in terms of the fraction of variance in SPVL controlled by the virus genotype. Methodology: We present computational methods which link statistics summarizing phylogenetic signal to heritability, h2 in order to test for and quantify it. We re-analyse data from Switzerland and Uganda, and apply it to new data from the Netherlands. We systematically compare established and new (e.g. phylogenetic pairs, PP) phylogenetic signal statistics. Results: Heritability estimates varied by method and dataset. Several methods were consistently able to detect simulated heritability above , but none below. Pagel’s λ was the most robust and sensitive. The PP method found no heritability in the Netherlands data, whereas Pagel’s λ found significant heritability only in a narrow subdivision (P =0.038). Heritability was estimated at h2=0.52 (95% confidence interval 0.00–0.63). Conclusions and implications: This standardized measure, h2, allows comparability of heritability between cohorts. We confirm high heritability in Swiss data, but neither in Ugandan data nor in the Netherlands, where it is barely significant or undetectable. Existing phylogenetic methods are ill-suited for detecting heritability below , which may nonetheless be biologically important.
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Affiliation(s)
- George Shirreff
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College, London, UK; Institute for Integrative Biology, ETH Zürich, Zürich, Switzerland; Lab MIVEGEC UMR CNRS 5290, IRD 224, UM1, UM2, Montpellier, France; Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zürich, University of Zürich, Zürich, Switzerland; National Institute of Allergy and Infectious Diseases, National Institutes of Health, Baltimore, MD, USA; Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; and Stichting HIV Monitoring, Amsterdam, The Netherlands
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17
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Ping LH, Joseph SB, Anderson JA, Abrahams MR, Salazar-Gonzalez JF, Kincer LP, Treurnicht FK, Arney L, Ojeda S, Zhang M, Keys J, Potter EL, Chu H, Moore P, Salazar MG, Iyer S, Jabara C, Kirchherr J, Mapanje C, Ngandu N, Seoighe C, Hoffman I, Gao F, Tang Y, Labranche C, Lee B, Saville A, Vermeulen M, Fiscus S, Morris L, Karim SA, Haynes BF, Shaw GM, Korber BT, Hahn BH, Cohen MS, Montefiori D, Williamson C, Swanstrom R. Comparison of viral Env proteins from acute and chronic infections with subtype C human immunodeficiency virus type 1 identifies differences in glycosylation and CCR5 utilization and suggests a new strategy for immunogen design. J Virol 2013; 87:7218-33. [PMID: 23616655 PMCID: PMC3700278 DOI: 10.1128/jvi.03577-12] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/15/2013] [Indexed: 12/18/2022] Open
Abstract
Understanding human immunodeficiency virus type 1 (HIV-1) transmission is central to developing effective prevention strategies, including a vaccine. We compared phenotypic and genetic variation in HIV-1 env genes from subjects in acute/early infection and subjects with chronic infections in the context of subtype C heterosexual transmission. We found that the transmitted viruses all used CCR5 and required high levels of CD4 to infect target cells, suggesting selection for replication in T cells and not macrophages after transmission. In addition, the transmitted viruses were more likely to use a maraviroc-sensitive conformation of CCR5, perhaps identifying a feature of the target T cell. We confirmed an earlier observation that the transmitted viruses were, on average, modestly underglycosylated relative to the viruses from chronically infected subjects. This difference was most pronounced in comparing the viruses in acutely infected men to those in chronically infected women. These features of the transmitted virus point to selective pressures during the transmission event. We did not observe a consistent difference either in heterologous neutralization sensitivity or in sensitivity to soluble CD4 between the two groups, suggesting similar conformations between viruses from acute and chronic infection. However, the presence or absence of glycosylation sites had differential effects on neutralization sensitivity for different antibodies. We suggest that the occasional absence of glycosylation sites encoded in the conserved regions of env, further reduced in transmitted viruses, could expose specific surface structures on the protein as antibody targets.
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Affiliation(s)
- Li-Hua Ping
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sarah B. Joseph
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jeffrey A. Anderson
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Melissa-Rose Abrahams
- Institute of Infectious Diseases and Molecular Medicine, Division of Medical Virology, University of Cape Town and National Health Laboratory Services, Cape Town, South Africa
| | | | - Laura P. Kincer
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Florette K. Treurnicht
- Institute of Infectious Diseases and Molecular Medicine, Division of Medical Virology, University of Cape Town and National Health Laboratory Services, Cape Town, South Africa
| | - Leslie Arney
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Suany Ojeda
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ming Zhang
- Theoretical Biology, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
- Department of Epidemiology and Biostatistics, University of Georgia, Athens, Georgia, USA
| | - Jessica Keys
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - E. Lake Potter
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Haitao Chu
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Penny Moore
- Centre for HIV and STIs, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Maria G. Salazar
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Shilpa Iyer
- Departments of Medicine and Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cassandra Jabara
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jennifer Kirchherr
- Duke Human Vaccine Institute, Department of Medicine, Duke University, Durham, North Carolina, USA
| | | | - Nobubelo Ngandu
- Institute of Infectious Diseases and Molecular Medicine, Division of Medical Virology, University of Cape Town and National Health Laboratory Services, Cape Town, South Africa
| | | | - Irving Hoffman
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Feng Gao
- Duke Human Vaccine Institute, Department of Medicine, Duke University, Durham, North Carolina, USA
| | - Yuyang Tang
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Celia Labranche
- Department of Surgery, Duke University, Durham, North Carolina, USA
| | - Benhur Lee
- Department of Microbiology, Immunology and Molecular Genetics, University of California at Los Angeles, Los Angeles, California, USA
| | - Andrew Saville
- South African National Blood Service, Weltevreden Park, South Africa
| | - Marion Vermeulen
- South African National Blood Service, Weltevreden Park, South Africa
| | - Susan Fiscus
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Lynn Morris
- Centre for HIV and STIs, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Salim Abdool Karim
- Center for AIDS Program Research in South Africa, Doris Duke Medical Research Institute, University of KwaZulu-Natal, Durban, South Africa
| | - Barton F. Haynes
- Duke Human Vaccine Institute, Department of Medicine, Duke University, Durham, North Carolina, USA
| | - George M. Shaw
- Departments of Medicine and Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bette T. Korber
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
- Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Beatrice H. Hahn
- Departments of Medicine and Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Myron S. Cohen
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - David Montefiori
- Department of Surgery, Duke University, Durham, North Carolina, USA
| | - Carolyn Williamson
- Institute of Infectious Diseases and Molecular Medicine, Division of Medical Virology, University of Cape Town and National Health Laboratory Services, Cape Town, South Africa
| | - Ronald Swanstrom
- UNC Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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18
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Aldous JL, Pond SK, Poon A, Jain S, Qin H, Kahn JS, Kitahata M, Rodriguez B, Dennis AM, Boswell SL, Haubrich R, Smith DM. Characterizing HIV transmission networks across the United States. Clin Infect Dis 2012; 55:1135-43. [PMID: 22784872 PMCID: PMC3529609 DOI: 10.1093/cid/cis612] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 06/29/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Clinically, human immunodeficiency virus type 1 (HIV-1) pol sequences are used to evaluate for drug resistance. These data can also be used to evaluate transmission networks and help describe factors associated with transmission risk. METHODS HIV-1 pol sequences from participants at 5 sites in the CFAR Network of Integrated Clinical Systems (CNICS) cohort from 2000-2009 were analyzed for genetic relatedness. Only the first available sequence per participant was included. Inferred transmission networks ("clusters") were defined as ≥2 sequences with ≤1.5% genetic distance. Clusters including ≥3 patients ("networks") were evaluated for clinical and demographic associations. RESULTS Of 3697 sequences, 24% fell into inferred clusters: 155 clusters of 2 individuals ("dyads"), 54 clusters that included 3-14 individuals ("networks"), and 1 large cluster that included 336 individuals across all study sites. In multivariable analyses, factors associated with being in a cluster included not using antiretroviral (ARV) drugs at time of sampling (P < .001), sequence collected after 2004 (P < .001), CD4 cell count >350 cells/mL (P < .01), and viral load 10,000-100,000 copies/mL (P < .001) or >100,000 copies/mL (P < .001). In networks, women were more likely to cluster with other women (P < .001), and African Americans with other African Americans (P < .001). CONCLUSIONS Molecular epidemiology can be applied to study HIV transmission networks in geographically and demographically diverse cohorts. Clustering was associated with lack of ARV use and higher viral load, implying transmission may be interrupted by earlier diagnosis and treatment. Observed female and African American networks reinforce the importance of diagnosis and prevention efforts targeted by sex and race.
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Affiliation(s)
- Jeannette L Aldous
- Division of Infectious Diseases, University of California, San Diego, 200 W Arbor Dr, MC 8208, San Diego, CA 92103, USA.
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19
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Higher HIV-1 genetic diversity is associated with AIDS and neuropsychological impairment. Virology 2012; 433:498-505. [PMID: 22999095 DOI: 10.1016/j.virol.2012.08.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 08/01/2012] [Accepted: 08/20/2012] [Indexed: 11/21/2022]
Abstract
Standard methods used to estimate HIV-1 population diversity are often resource intensive (e.g., single genome amplification, clonal amplification and pyrosequencing) and not well suited for large study cohorts. Additional approaches are needed to address the relationships between intraindividual HIV-1 genetic diversity and 2 disease. With a small cohort of individuals, we validated three methods for measuring diversity: Shannon entropy and average pairwise distance (APD) using single genome sequences, and counts of mixed bases (i.e. ambiguous nucleotides) from population based sequences. In a large cohort, we then used the mixed base approach to determine associations between measure HIV-1 diversity and HIV associated disease. Normalized counts of mixed bases correlated with Shannon Entropy at both the nucleotide (rho=0.72, p=0.002) and amino acid level (rho=0.59, p=0.015), and APD (rho=0.75, p=0.001). Among participants who underwent neuropsychological and clinical assessments (n=187), increased HIV-1 population diversity was associated with both a diagnosis of AIDS and neuropsychological impairment.
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20
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Mostowy R, Kouyos RD, Hoof I, Hinkley T, Haddad M, Whitcomb JM, Petropoulos CJ, Keşmir C, Bonhoeffer S. Estimating the fitness cost of escape from HLA presentation in HIV-1 protease and reverse transcriptase. PLoS Comput Biol 2012; 8:e1002525. [PMID: 22654656 PMCID: PMC3359966 DOI: 10.1371/journal.pcbi.1002525] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 04/03/2012] [Indexed: 12/11/2022] Open
Abstract
Human immunodeficiency virus (HIV-1) is, like most pathogens, under selective pressure to escape the immune system of its host. In particular, HIV-1 can avoid recognition by cytotoxic T lymphocytes (CTLs) by altering the binding affinity of viral peptides to human leukocyte antigen (HLA) molecules, the role of which is to present those peptides to the immune system. It is generally assumed that HLA escape mutations carry a replicative fitness cost, but these costs have not been quantified. In this study, we assess the replicative cost of mutations which are likely to escape presentation by HLA molecules in the region of HIV-1 protease and reverse transcriptase. Specifically, we combine computational approaches for prediction of in vitro replicative fitness and peptide binding affinity to HLA molecules. We find that mutations which impair binding to HLA-A molecules tend to have lower in vitro replicative fitness than mutations which do not impair binding to HLA-A molecules, suggesting that HLA-A escape mutations carry higher fitness costs than non-escape mutations. We argue that the association between fitness and HLA-A binding impairment is probably due to an intrinsic cost of escape from HLA-A molecules, and these costs are particularly strong for HLA-A alleles associated with efficient virus control. Counter-intuitively, we do not observe a significant effect in the case of HLA-B, but, as discussed, this does not argue against the relevance of HLA-B in virus control. Overall, this article points to the intriguing possibility that HLA-A molecules preferentially target more conserved regions of HIV-1, emphasizing the importance of HLA-A genes in the evolution of HIV-1 and RNA viruses in general. Our immune system can recognize and kill virus-infected cells by distinguishing between self and virus-derived protein fragments, called peptides, displayed on the surface of each cell. One requirement for a successful recognition is that those peptides bind to the human leukocyte antigen (HLA) class I molecules, which present them to the immune system. As a counter-strategy, human immunodeficiency virus type 1 (HIV-1) can acquire mutations that prevent this binding, thereby helping the virus to escape the surveillance of T-lymphocytes. It is likely that the virus pays a replicative cost for such escape mutations, but the magnitude of this cost has remained elusive. Here, we quantified this fitness cost in HIV-1 protease and reverse transcriptase by combining two computational systems biology approaches: one for prediction of in vitro replicative fitness, and one for the prediction of the efficiency of peptide binding to HLA. We found that in viral proteins targeted by HLA-A molecules, mutations which disrupt binding to those molecules carry a lower replicative fitness than mutations which do not have such an effect. We argue that these results are consistent with the hypothesis that our immune systems might have evolved to target genetic regions of RNA viruses which are costly for the pathogen to alter.
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Affiliation(s)
- Rafal Mostowy
- Institute for Integrative Biology, ETH Zurich, Zurich, Switzerland.
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21
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Knapp DJHF, Brumme ZL, Huang SY, Wynhoven B, Dong WWY, Mo T, Harrigan PR, Brumme CJ. Increasingly Successful Highly Active Antiretroviral Therapy Delays the Emergence of New HLA Class I–Associated Escape Mutations in HIV-1. Clin Infect Dis 2012; 54:1652-9. [DOI: 10.1093/cid/cis253] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Castro-Nallar E, Pérez-Losada M, Burton GF, Crandall KA. The evolution of HIV: inferences using phylogenetics. Mol Phylogenet Evol 2012; 62:777-92. [PMID: 22138161 PMCID: PMC3258026 DOI: 10.1016/j.ympev.2011.11.019] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 11/17/2011] [Accepted: 11/21/2011] [Indexed: 12/02/2022]
Abstract
Molecular phylogenetics has revolutionized the study of not only evolution but also disparate fields such as genomics, bioinformatics, epidemiology, ecology, microbiology, molecular biology and biochemistry. Particularly significant are its achievements in population genetics as a result of the development of coalescent theory, which have contributed to more accurate model-based parameter estimation and explicit hypothesis testing. The study of the evolution of many microorganisms, and HIV in particular, have benefited from these new methodologies. HIV is well suited for such sophisticated population analyses because of its large population sizes, short generation times, high substitution rates and relatively small genomes. All these factors make HIV an ideal and fascinating model to study molecular evolution in real time. Here we review the significant advances made in HIV evolution through the application of phylogenetic approaches. We first examine the relative roles of mutation and recombination on the molecular evolution of HIV and its adaptive response to drug therapy and tissue allocation. We then review some of the fundamental questions in HIV evolution in relation to its origin and diversification and describe some of the insights gained using phylogenies. Finally, we show how phylogenetic analysis has advanced our knowledge of HIV dynamics (i.e., phylodynamics).
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Affiliation(s)
- Eduardo Castro-Nallar
- Department of Biology, 401 Widtsoe Building, Brigham Young University, Provo, UT 84602-5181, USA.
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Poulicard N, Pinel-Galzi A, Traoré O, Vignols F, Ghesquière A, Konaté G, Hébrard E, Fargette D. Historical contingencies modulate the adaptability of Rice yellow mottle virus. PLoS Pathog 2012; 8:e1002482. [PMID: 22291591 PMCID: PMC3266926 DOI: 10.1371/journal.ppat.1002482] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 11/29/2011] [Indexed: 12/28/2022] Open
Abstract
The rymv1-2 and rymv1-3 alleles of the RYMV1 resistance to Rice yellow mottle virus (RYMV), coded by an eIF(iso)4G1 gene, occur in a few cultivars of the Asiatic (Oryza sativa) and African (O. glaberrima) rice species, respectively. The most salient feature of the resistance breaking (RB) process is the converse genetic barrier to rymv1-2 and rymv1-3 resistance breakdown. This specificity is modulated by the amino acid (glutamic acid vs. threonine) at codon 49 of the Viral Protein genome-linked (VPg), a position which is adjacent to the virulence codons 48 and 52. Isolates with a glutamic acid (E) do not overcome rymv1-3 whereas those with a threonine (T) rarely overcome rymv1-2. We found that isolates with T49 had a strong selective advantage over isolates with E49 in O. glaberrima susceptible cultivars. This explains the fixation of the mutation T49 during RYMV evolution and accounts for the diversifying selection estimated at codon 49. Better adapted to O. glaberrima, isolates with T49 are also more prone than isolates with E49 to fix rymv1-3 RB mutations at codon 52 in resistant O. glaberrima cultivars. However, subsequent genetic constraints impaired the ability of isolates with T49 to fix rymv1-2 RB mutations at codons 48 and 52 in resistant O. sativa cultivars. The origin and role of the amino acid at codon 49 of the VPg exemplifies the importance of historical contingencies in the ability of RYMV to overcome RYMV1 resistance.
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Affiliation(s)
- Nils Poulicard
- Institut de Recherche pour le Développement (IRD), UMR RPB (IRD, CIRAD, Université Montpellier 2), Montpellier, France
| | - Agnès Pinel-Galzi
- Institut de Recherche pour le Développement (IRD), UMR RPB (IRD, CIRAD, Université Montpellier 2), Montpellier, France
| | - Oumar Traoré
- Institut de l'Environnement et de Recherches Agricoles (INERA), Ouagadougou, Burkina-Faso
| | - Florence Vignols
- Institut de Recherche pour le Développement (IRD), UMR RPB (IRD, CIRAD, Université Montpellier 2), Montpellier, France
| | - Alain Ghesquière
- Institut de Recherche pour la Développement (IRD), UMR DIADE (IRD, CIRAD, Université Montpellier 2), Montpellier, France
| | - Gnissa Konaté
- Institut de l'Environnement et de Recherches Agricoles (INERA), Ouagadougou, Burkina-Faso
| | - Eugénie Hébrard
- Institut de Recherche pour le Développement (IRD), UMR RPB (IRD, CIRAD, Université Montpellier 2), Montpellier, France
| | - Denis Fargette
- Institut de Recherche pour le Développement (IRD), UMR RPB (IRD, CIRAD, Université Montpellier 2), Montpellier, France
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Poon AF, McGovern RA, Mo T, Knapp DJ, Brenner B, Routy JP, Wainberg MA, Harrigan PR. Dates of HIV infection can be estimated for seroprevalent patients by coalescent analysis of serial next-generation sequencing data. AIDS 2011; 25:2019-26. [PMID: 21832936 DOI: 10.1097/qad.0b013e32834b643c] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To reconstruct dates of HIV infection by the coalescent analysis of longitudinal next-generation sequencing (NGS) data. DESIGN The coalescent predicts the time that has elapsed since the most recent common ancestor (MRCA) of a population. Because HIV tends to undergo severe bottlenecks upon transmission, the MRCA may be a good predictor of the time of infection. NGS provides an efficient means for performing large-scale clonal sequencing of HIV populations within patients, and the ideal raw material for coalescent analysis. METHODS Baseline and follow-up plasma samples were obtained from 19 individuals enrolled into the Montréal Primary HIV Infection cohort. Dates of infection were initially estimated at baseline from nongenetic data (clinical and serological markers and patient questionnaires). HIV RNA was extracted and seven regions of the genome were amplified, subjected to parallel-tagged 454 pyrosequencing, and analyzed using the software package BEAST. RESULTS Mean estimates of the time to the MRCA per patient were significantly correlated with nongenetic estimates (Spearman's ρ = 0.65, P = 4.4 × 10(-3)). The median absolute difference between coalescent and nongenetic date estimates was smallest (median 29.4 days) for highly variable regions of the HIV genome such as env V3, and greater (median 114.9 days) for more conserved regions such as pol. CONCLUSION This application of NGS represents an important advancement, not only because accurate estimates of dates of infection can be derived retrospectively from archived specimens, but also because each analysis is patient-specific and, therefore, robust to variation in rates of HIV evolution.
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McMullen AR, May FJ, Li L, Guzman H, Bueno R, Dennett JA, Tesh RB, Barrett ADT. Evolution of new genotype of West Nile virus in North America. Emerg Infect Dis 2011; 17:785-93. [PMID: 21529385 PMCID: PMC3321787 DOI: 10.3201/eid1705.101707] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Previous studies of North American isolates of West Nile virus (WNV) during 1999–2005 suggested that the virus had reached genetic homeostasis in North America. However, genomic sequencing of WNV isolates from Harris County, Texas, during 2002–2009 suggests that this is not the case. Three new genetic groups have been identified in Texas since 2005. Spread of the southwestern US genotype (SW/WN03) from the Arizona/Colorado/northern Mexico region to California, Illinois, New Mexico, New York, North Dakota, and the Texas Gulf Coast demonstrates continued evolution of WNV. Thus, WNV continues to evolve in North America, as demonstrated by selection of this new genotype. Continued surveillance of the virus is essential as it continues to evolve in the New World.
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Compensatory mutations restore the replication defects caused by cytotoxic T lymphocyte escape mutations in hepatitis C virus polymerase. J Virol 2011; 85:11883-90. [PMID: 21880756 DOI: 10.1128/jvi.00779-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
While human leukocyte antigen B57 (HLA-B57) is associated with the spontaneous clearance of hepatitis C virus (HCV), the mechanisms behind this control remain unclear. Immunodominant CD8(+) T cell responses against the B57-restricted epitopes comprised of residues 2629 to 2637 of nonstructural protein 5B (NS5B(2629-2637)) (KSKKTPMGF) and E2(541-549) (NTRPPLGNW) were recently shown to be crucial in the control of HCV infection. Here, we investigated whether the selection of deleterious cytotoxic T lymphocyte (CTL) escape mutations in the NS5B KSKKTPMGF epitope might impair viral replication and contribute to the B57-mediated control of HCV. Common CTL escape mutations in this epitope were identified from a cohort of 374 HCV genotype 1a-infected subjects, and their impact on HCV replication assessed using a transient HCV replicon system. We demonstrate that while escape mutations at residue 2633 (position 5) of the epitope had little or no impact on HCV replication in vitro, mutations at residue 2629 (position 1) substantially impaired replication. Notably, the deleterious mutations at position 2629 were tightly linked in vivo to upstream mutations at residue 2626, which functioned to restore the replicative defects imparted by the deleterious escape mutations. These data suggest that the selection of costly escape mutations within the immunodominant NS5B KSKKTPMGF epitope may contribute in part to the control of HCV replication in B57-positive individuals and that persistence of HCV in B57-positive individuals may involve the development of specific secondary compensatory mutations. These findings are reminiscent of the selection of deleterious CTL escape and compensatory mutations by HLA-B57 in HIV-1 infection and, thus, may suggest a common mechanism by which alleles like HLA-B57 mediate protection against these highly variable pathogens.
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Abstract
The hepatitis C virus (HCV) is a global public health problem affecting approximately 2% of the human population. The majority of HCV infections (more than 70%) result in life-long persistence of the virus that substantially increases the risk of serious liver diseases, including cirrhosis and hepatocellular carcinoma. The remainder (less than 30%) resolves spontaneously, often resulting in long-lived protection from persistence upon reexposure to the virus. To persist, the virus must replicate and this requires effective evasion of adaptive immune responses. In this review, the role of humoral and cellular immunity in preventing HCV persistence, and the mechanisms used by the virus to subvert protective host responses, are considered.
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Pacold M, Smith D, Little S, Cheng PM, Jordan P, Ignacio C, Richman D, Pond SK. Comparison of methods to detect HIV dual infection. AIDS Res Hum Retroviruses 2010; 26:1291-8. [PMID: 20954840 DOI: 10.1089/aid.2010.0042] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Current methods to detect intraclade HIV dual infection are poorly suited for determining its prevalence in large cohorts. To investigate the potential of ultra-deep sequencing to screen for dual infection, we compared it to bulk sequence-based synonymous mixture index and the current standard of single genome sequencing. The synonymous mixture index identified samples likely to harbor dual infection, while ultra-deep sequencing captured more intra-host viral diversity than single genome sequencing at approximately 40% of the cost and 20% of the laboratory and analysis time. The synonymous mixture index and ultra-deep sequencing are promising methods for rapid and cost-effective systematic identification of HIV dual infection.
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Affiliation(s)
- Mary Pacold
- University of California, San Diego, La Jolla, California
| | - Davey Smith
- University of California, San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Susan Little
- University of California, San Diego, La Jolla, California
| | - Pok Man Cheng
- University of California, San Diego, La Jolla, California
| | - Parris Jordan
- University of California, San Diego, La Jolla, California
| | | | - Douglas Richman
- University of California, San Diego, La Jolla, California
- Veterans Affairs San Diego Healthcare System, San Diego, California
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Modelling the evolution and spread of HIV immune escape mutants. PLoS Pathog 2010; 6:e1001196. [PMID: 21124991 PMCID: PMC2987822 DOI: 10.1371/journal.ppat.1001196] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 10/15/2010] [Indexed: 02/07/2023] Open
Abstract
During infection with human immunodeficiency virus (HIV), immune pressure from cytotoxic T-lymphocytes (CTLs) selects for viral mutants that confer escape from CTL recognition. These escape variants can be transmitted between individuals where, depending upon their cost to viral fitness and the CTL responses made by the recipient, they may revert. The rates of within-host evolution and their concordant impact upon the rate of spread of escape mutants at the population level are uncertain. Here we present a mathematical model of within-host evolution of escape mutants, transmission of these variants between hosts and subsequent reversion in new hosts. The model is an extension of the well-known SI model of disease transmission and includes three further parameters that describe host immunogenetic heterogeneity and rates of within host viral evolution. We use the model to explain why some escape mutants appear to have stable prevalence whilst others are spreading through the population. Further, we use it to compare diverse datasets on CTL escape, highlighting where different sources agree or disagree on within-host evolutionary rates. The several dozen CTL epitopes we survey from HIV-1 gag, RT and nef reveal a relatively sedate rate of evolution with average rates of escape measured in years and reversion in decades. For many epitopes in HIV, occasional rapid within-host evolution is not reflected in fast evolution at the population level. HIV evolves so quickly that it can be seen to adapt within one infected person. Evolutionary escape from immunity is particularly well-described. Escape variants transmit to new hosts, where they may revert. We present a mathematical model of three processes: within-host evolution of escape mutants, transmission of those variants between hosts and subsequent reversion in new hosts. Using this model we reconcile diverse datasets on HIV immune escape, highlighting where multiple data sources agree or disagree on the underlying rate processes. The several-dozen immune epitopes we survey reveal a relatively sedate rate of evolution with average rates of escape measured in years and reversion in decades. Although there are frequent reports in the literature of early and rapid within-host evolution of HIV, for many epitopes this is not reflected in fast evolution at the population level.
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Alizon S, Luciani F, Regoes RR. Epidemiological and clinical consequences of within-host evolution. Trends Microbiol 2010; 19:24-32. [PMID: 21055948 DOI: 10.1016/j.tim.2010.09.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 09/14/2010] [Accepted: 09/28/2010] [Indexed: 11/18/2022]
Abstract
Many viruses and bacteria are known to evolve rapidly over the course of an infection. However, epidemiological studies generally assume that within-host evolution is an instantaneous process. We argue that the dynamics of within-host evolution has implications at the within-host and at the between-host levels. We first show that epidemiologists should consider within-host evolution, notably because it affects the genotype of the pathogen that is transmitted. We then present studies that investigate evolution at the within-host level and examine the extent to which these studies can help to understand infection traits involved in the epidemiology (e.g. transmission rate, virulence, recovery rate). Finally, we discuss how new techniques for data acquisition can open new perspectives for empirical and theoretical research.
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Affiliation(s)
- Samuel Alizon
- Laboratoire Génétique et Évolution des Maladies Infectieuses, Unité Mixte de Recherche du Centre national de la Recherche Scientifique et de l'Institut de Recherche pour le Développement 2724, 911 avenue Agropolis, BP 64501, 34394 Montpellier CEDEX 5, France.
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Rolland M, Carlson JM, Manocheewa S, Swain JV, Lanxon-Cookson E, Deng W, Rousseau CM, Raugi DN, Learn GH, Maust BS, Coovadia H, Ndung'u T, Goulder PJR, Walker BD, Brander C, Heckerman DE, Mullins JI. Amino-acid co-variation in HIV-1 Gag subtype C: HLA-mediated selection pressure and compensatory dynamics. PLoS One 2010; 5. [PMID: 20824187 PMCID: PMC2931691 DOI: 10.1371/journal.pone.0012463] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 07/30/2010] [Indexed: 11/19/2022] Open
Abstract
Background Despite high potential for HIV-1 genetic variation, the emergence of some mutations is constrained by fitness costs, and may be associated with compensatory amino acid (AA) co-variation. To characterize the interplay between Cytotoxic T Lymphocyte (CTL)-mediated pressure and HIV-1 evolutionary pathways, we investigated AA co-variation in Gag sequences obtained from 449 South African individuals chronically infected with HIV-1 subtype C. Methodology/Principal Findings Individuals with CTL responses biased toward Gag presented lower viral loads than individuals with under-represented Gag-specific CTL responses. Using methods that account for founder effects and HLA linkage disequilibrium, we identified 35 AA sites under Human Leukocyte Antigen (HLA)-restricted CTL selection pressure and 534 AA-to-AA interactions. Analysis of two-dimensional distances between co-varying residues revealed local stabilization mechanisms since 40% of associations involved neighboring residues. Key features of our co-variation analysis included sites with a high number of co-varying partners, such as HLA-associated sites, which had on average 55% more connections than other co-varying sites. Conclusions/Significance Clusters of co-varying AA around HLA-associated sites (especially at typically conserved sites) suggested that cooperative interactions act to preserve the local structural stability and protein function when CTL escape mutations occur. These results expose HLA-imprinted HIV-1 polymorphisms and their interlinked mutational paths in Gag that are likely due to opposite selective pressures from host CTL-mediated responses and viral fitness constraints.
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Affiliation(s)
- Morgane Rolland
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America.
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González-Candelas F, López-Labrador FX. Clinical relevance of genetic heterogeneity in HCV. Future Virol 2010. [DOI: 10.2217/fvl.09.63] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Infection by HCV affects an estimated 170 million people worldwide and it represents one of the major causes of liver transplantation and a heavy burden to healthcare systems. As with many other RNA viruses, HCV is characterized by very high levels of genetic variation, which have been associated to differences in disease progression and efficiency of antiviral treatment. Studies show many contradictory results and little consensus on such associations. Nevertheless, some general guidelines translating research results to clinical practice have been postulated. Here, we review the main research results obtained on HCV variation so far and explore the reasons for their lack of congruence under a population genetics framework. Understanding the factors responsible for the variable dynamics of HCV diversity in human populations and variation within infected individuals is even more necessary in face of the soon-to-arrive new HCV therapies.
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Affiliation(s)
- Fernando González-Candelas
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Apartado Oficial 22085, 46071-Valencia, Spain
| | - F Xavier López-Labrador
- Genomics and Health Area, CSISP – Centre for Public Health Research, Public Health Department, Generalitat Valenciana, Av. Catalunya, 21, 46020 Valencia, Spain
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Irausquin SJ, Hughes AL. Conflicting selection pressures target the NS3 protein in hepatitis C virus genotypes 1a and 1b. Virus Res 2009; 147:202-7. [PMID: 19896990 DOI: 10.1016/j.virusres.2009.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 10/28/2009] [Accepted: 11/02/2009] [Indexed: 01/06/2023]
Abstract
Analysis of complete polyprotein-encoding sequences of the two most prevalent genotypes of hepatitis C virus (HCV-1a and HCV-1b) revealed evidence of abundant, slightly deleterious nonsynonymous variants subject to ongoing purifying selection. In the case of both HCV-1a and HCV-1b, the NS3 protein demonstrated a high incidence of forward-and-backward or parallel nonsynonymous changes in CTL epitopes as measured by the phylogenetic consistency index. These results imply that certain nonsynonymous mutations have occurred frequently throughout the HCV-1a and HCV-1b phylogenies in the codons encoding the epitopes in NS3. This pattern is best explained by the frequent re-occurrence of the same set of escape mutations in CTL epitopes of NS3, which are selectively favored within hosts presenting the class I major histocompatability complex molecule, but subject to purifying selection in the population at large. This pattern was more pronounced in HCV-1b than in HCV-1a, suggesting that there may be differences between the two genotypes with respect to NS3's interaction with host immune recognition.
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Schmid BV, Keşmir C, de Boer RJ. The distribution of CTL epitopes in HIV-1 appears to be random, and similar to that of other proteomes. BMC Evol Biol 2009; 9:184. [PMID: 19653887 PMCID: PMC3087517 DOI: 10.1186/1471-2148-9-184] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 08/04/2009] [Indexed: 11/20/2022] Open
Abstract
Background HIV-1 viruses are highly capable of mutating their proteins to escape the presentation of CTL epitopes in their current host. Upon transmission to another host, some escape mutations revert, but other remain stable in the virus sequence for at least several years. Depending on the rate of accumulation and reversion of escape mutations, HIV-1 could reach a high level of adaptation to the human population. Yusim et. al. hypothesized that the apparent clustering of CTL epitopes in the conserved regions of HIV-1 proteins could be an evolutionary signature left by large-scale adaptation of HIV-1 to its human/simian host. Results In this paper we quantified the distribution of CTL epitopes in HIV-1 and found that that in 99% of the HIV-1 protein sequences, the epitope distribution was indistinguishable from random. Similar percentages were found for HCV, Influenza and for three eukaryote proteomes (Human, Drosophila, Yeast). Conclusion We conclude that CTL epitopes in HIV-1 are randomly distributed, and that this distribution is similar to the distribution of CTL epitopes in proteins from other proteomes. Therefore, the visually apparent clustering of CTL epitopes in epitope maps should not be interpreted as a signature of a past large-scale adaptation of HIV-1 to the human cellular immune response.
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Affiliation(s)
- Boris V Schmid
- Theoretical Biology, Utrecht University, the Netherlands.
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Kosakovsky Pond SL, Smith DM. Are all subtypes created equal? The effectiveness of antiretroviral therapy against non-subtype B HIV-1. Clin Infect Dis 2009; 48:1306-9. [PMID: 19331584 DOI: 10.1086/598503] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Genetic characterization of hepatitis B virus in peripheral blood leukocytes: evidence for selection and compartmentalization of viral variants with the immune escape G145R mutation. J Virol 2009; 83:9983-92. [PMID: 19420079 DOI: 10.1128/jvi.01905-08] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The compartmentalization of viral variants in distinct host tissues is a frequent event in many viral infections. Although hepatitis B virus (HBV) classically is considered hepatotropic, it has strong lymphotropic properties as well. However, unlike other viruses, molecular evolutionary studies to characterize HBV variants in compartments other than hepatocytes or sera have not been performed. The present work attempted to characterize HBV sequences from the peripheral blood leukocytes (PBL) of a large set of subjects, using advanced molecular biology and computational methods. The results of this study revealed the exclusive compartmentalization of HBV subgenotype Ae/A2-specific sequences with a potent immune escape G145R mutation in the PBL of the majority of the subjects. Interestingly, entirely different HBV genotypes/subgenotypes (C, D, or Aa/A1) were found to predominate in the sera of the same study populations. These results suggest that subgenotype Ae/A2 is selectively archived in the PBL, and the high prevalence of G145R indicates high immune pressure and high evolutionary rates of HBV DNA in the PBL. The results are analogous to available literature on the compartmentalization of other viruses. The present work thus provides evidence in favor of the compartment-specific abundance, evolution, and emergence of the potent immune escape mutant. These findings have important implications in the field of HBV molecular epidemiology, transmission, transfusion medicine, organ transplantation, and vaccination strategies.
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Abstract
Immune function is likely to be a critical determinant of an organism's fitness, yet most natural animal and plant populations exhibit tremendous genetic variation for immune traits. Accumulating evidence suggests that environmental heterogeneity may retard the long-term efficiency of natural selection and even maintain polymorphism, provided alternative host genotypes are favoured under different environmental conditions. 'Environment' in this context refers to abiotic factors such as ambient temperature or availability of nutrient resources, genetic diversity of pathogens or competing physiological demands on the host. These factors are generally controlled in laboratory experiments measuring immune performance, but variation in them is likely to be very important in the evolution of resistance to infection. Here, we review some of the literature emphasizing the complexity of natural selection on immunity. Our aim is to describe how environmental and genetic heterogeneities, often excluded from experimentation as 'noise', may determine the evolutionary potential of populations or the potential for interacting species to coevolve.
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Affiliation(s)
- Brian P Lazzaro
- Department of Entomology, Cornell University, Ithaca, NY 14850, USA.
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Delport W, Scheffler K, Seoighe C. Frequent toggling between alternative amino acids is driven by selection in HIV-1. PLoS Pathog 2008; 4:e1000242. [PMID: 19096508 PMCID: PMC2592544 DOI: 10.1371/journal.ppat.1000242] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 11/18/2008] [Indexed: 11/19/2022] Open
Abstract
Host immune responses against infectious pathogens exert strong selective pressures favouring the emergence of escape mutations that prevent immune recognition. Escape mutations within or flanking functionally conserved epitopes can occur at a significant cost to the pathogen in terms of its ability to replicate effectively. Such mutations come under selective pressure to revert to the wild type in hosts that do not mount an immune response against the epitope. Amino acid positions exhibiting this pattern of escape and reversion are of interest because they tend to coincide with immune responses that control pathogen replication effectively. We have used a probabilistic model of protein coding sequence evolution to detect sites in HIV-1 exhibiting a pattern of rapid escape and reversion. Our model is designed to detect sites that toggle between a wild type amino acid, which is susceptible to a specific immune response, and amino acids with lower replicative fitness that evade immune recognition. Through simulation, we show that this model has significantly greater power to detect selection involving immune escape and reversion than standard models of diversifying selection, which are sensitive to an overall increased rate of non-synonymous substitution. Applied to alignments of HIV-1 protein coding sequences, the model of immune escape and reversion detects a significantly greater number of adaptively evolving sites in env and nef. In all genes tested, the model provides a significantly better description of adaptively evolving sites than standard models of diversifying selection. Several of the sites detected are corroborated by association between Human Leukocyte Antigen (HLA) and viral sequence polymorphisms. Overall, there is evidence for a large number of sites in HIV-1 evolving under strong selective pressure, but exhibiting low sequence diversity. A phylogenetic model designed to detect rapid toggling between wild type and escape amino acids identifies a larger number of adaptively evolving sites in HIV-1, and can in some cases correctly identify the amino acid that is susceptible to the immune response. Viruses, such as HIV, are able to evade host immune responses through escape mutations, yet sometimes they do so at a cost. This cost is the reduction in the ability of the virus to replicate, and thus selective pressure exists for a virus to revert to its original state in the absence of the host immune response that caused the initial escape mutation. This pattern of escape and reversion typically occurs when viruses are transmitted between individuals with different immune responses. We develop a phylogenetic model of immune escape and reversion and provide evidence that it outperforms existing models for the detection of selective pressure associated with host immune responses. Finally, we demonstrate that amino acid toggling is a pervasive process in HIV-1 evolution, such that many of the positions in the virus that evolve rapidly, under the influence of positive Darwinian selection, nonetheless display quite low sequence diversity. This highlights the limitations of HIV-1 evolution, and sites such as these are potentially good targets for HIV-1 vaccines.
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Affiliation(s)
- Wayne Delport
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town, South Africa
- Centre for High-Performance Computing, Rosebank, Cape Town, South Africa
| | - Konrad Scheffler
- Computer Science Division, Department of Mathematical Sciences, University of Stellenbosch, Stellenbosch, South Africa
| | - Cathal Seoighe
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town, South Africa
- Centre for High-Performance Computing, Rosebank, Cape Town, South Africa
- * E-mail:
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Protective HLA class I alleles that restrict acute-phase CD8+ T-cell responses are associated with viral escape mutations located in highly conserved regions of human immunodeficiency virus type 1. J Virol 2008; 83:1845-55. [PMID: 19036810 DOI: 10.1128/jvi.01061-08] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The control of human immunodeficiency virus type 1 (HIV-1) associated with particular HLA class I alleles suggests that some CD8(+) T-cell responses may be more effective than others at containing HIV-1. Unfortunately, substantial diversities in the breadth, magnitude, and function of these responses have impaired our ability to identify responses most critical to this control. It has been proposed that CD8 responses targeting conserved regions of the virus may be particularly effective, since the development of cytotoxic T-lymphocyte (CTL) escape mutations in these regions may significantly impair viral replication. To address this hypothesis at the population level, we derived near-full-length viral genomes from 98 chronically infected individuals and identified a total of 76 HLA class I-associated mutations across the genome, reflective of CD8 responses capable of selecting for sequence evolution. The majority of HLA-associated mutations were found in p24 Gag, Pol, and Nef. Reversion of HLA-associated mutations in the absence of the selecting HLA allele was also commonly observed, suggesting an impact of most CTL escape mutations on viral replication. Although no correlations were observed between the number or location of HLA-associated mutations and protective HLA alleles, limiting the analysis to mutations selected by acute-phase immunodominant responses revealed a strong positive correlation between mutations at conserved residues and protective HLA alleles. These data suggest that control of HIV-1 may be associated with acute-phase CD8 responses capable of selecting for viral escape mutations in highly conserved regions of the virus, supporting the inclusion of these regions in the design of an effective vaccine.
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The specificity and polymorphism of the MHC class I prevents the global adaptation of HIV-1 to the monomorphic proteasome and TAP. PLoS One 2008; 3:e3525. [PMID: 18949050 PMCID: PMC2569417 DOI: 10.1371/journal.pone.0003525] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 09/29/2008] [Indexed: 11/19/2022] Open
Abstract
The large diversity in MHC class I molecules in a population lowers the chance that a virus infects a host to which it is pre-adapted to escape the MHC binding of CTL epitopes. However, viruses can also lose CTL epitopes by escaping the monomorphic antigen processing components of the pathway (proteasome and TAP) that create the epitope precursors. If viruses were to accumulate escape mutations affecting these monomorphic components, they would become pre-adapted to all hosts regardless of the MHC polymorphism. To assess whether viruses exploit this apparent vulnerability, we study the evolution of HIV-1 with bioinformatic tools that allow us to predict CTL epitopes, and quantify the frequency and accumulation of antigen processing escapes. We found that within hosts, proteasome and TAP escape mutations occur frequently. However, on the population level these escapes do not accumulate: the total number of predicted epitopes and epitope precursors in HIV-1 clade B has remained relatively constant over the last 30 years. We argue that this lack of adaptation can be explained by the combined effect of the MHC polymorphism and the high specificity of individual MHC molecules. Because of these two properties, only a subset of the epitope precursors in a host are potential epitopes, and that subset differs between hosts. We estimate that upon transmission of a virus to a new host 39%–66% of the mutations that caused epitope precursor escapes are released from immune selection pressure.
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Irausquin SJ, Hughes AL. Distinctive pattern of sequence polymorphism in the NS3 protein of hepatitis C virus type 1b reflects conflicting evolutionary pressures. J Gen Virol 2008; 89:1921-1929. [PMID: 18632963 DOI: 10.1099/vir.0.2008/000992-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Analysis of complete polyprotein-encoding sequences of hepatitis C virus genotype 1b (HCV-1b) showed evidence not only of past purifying selection but also of abundant slightly deleterious non-synonymous variants subject to ongoing purifying selection. The NS3 protein (with protease and NTPase/helicase activity) revealed less evidence of purifying selection acting on the cytotoxic T cells (CTL) epitopes than did the other proteins, whereas outside the CTL epitopes NS3 was more conserved than the other proteins. Moreover, NS3 showed a high incidence of forward-and-backward or parallel non-synonymous changes in CTL epitopes, as measured by the consistency index across the phylogeny of HCV-1b genomes computed at non-singleton non-synonymous polymorphic sites. This result implies that certain non-synonymous mutations have recurred frequently throughout the phylogeny in the codons encoding the epitopes in NS3. This pattern is most easily explained by the frequent re-occurrence of the same set of escape mutations in CTL epitopes of NS3, which are selectively favoured within hosts expressing the presenting class I major histocompatibility complex molecule, but are subject to purifying selection at the population level. The fact that this pattern is most strikingly observed in the case of NS3 suggests that the evolutionary conflict between immune escape and functional constraint on the protein is more acute in the case of NS3 than any of the other proteins of HCV-1b.
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Affiliation(s)
| | - Austin L Hughes
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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Rousseau CM, Daniels MG, Carlson JM, Kadie C, Crawford H, Prendergast A, Matthews P, Payne R, Rolland M, Raugi DN, Maust BS, Learn GH, Nickle DC, Coovadia H, Ndung'u T, Frahm N, Brander C, Walker BD, Goulder PJR, Bhattacharya T, Heckerman DE, Korber BT, Mullins JI. HLA class I-driven evolution of human immunodeficiency virus type 1 subtype c proteome: immune escape and viral load. J Virol 2008; 82:6434-46. [PMID: 18434400 PMCID: PMC2447109 DOI: 10.1128/jvi.02455-07] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 04/11/2008] [Indexed: 01/02/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) mutations that confer escape from cytotoxic T-lymphocyte (CTL) recognition can sometimes result in lower viral fitness. These mutations can then revert upon transmission to a new host in the absence of CTL-mediated immune selection pressure restricted by the HLA alleles of the prior host. To identify these potentially critical recognition points on the virus, we assessed HLA-driven viral evolution using three phylogenetic correction methods across full HIV-1 subtype C proteomes from a cohort of 261 South Africans and identified amino acids conferring either susceptibility or resistance to CTLs. A total of 558 CTL-susceptible and -resistant HLA-amino acid associations were identified and organized into 310 immunological sets (groups of individual associations related to a single HLA/epitope combination). Mutations away from seven susceptible residues, including four in Gag, were associated with lower plasma viral-RNA loads (q < 0.2 [where q is the expected false-discovery rate]) in individuals with the corresponding HLA alleles. The ratio of susceptible to resistant residues among those without the corresponding HLA alleles varied in the order Vpr > Gag > Rev > Pol > Nef > Vif > Tat > Env > Vpu (Fisher's exact test; P < or = 0.0009 for each comparison), suggesting the same ranking of fitness costs by genes associated with CTL escape. Significantly more HLA-B (chi(2); P = 3.59 x 10(-5)) and HLA-C (chi(2); P = 4.71 x 10(-6)) alleles were associated with amino acid changes than HLA-A, highlighting their importance in driving viral evolution. In conclusion, specific HIV-1 residues (enriched in Vpr, Gag, and Rev) and HLA alleles (particularly B and C) confer susceptibility to the CTL response and are likely to be important in the development of vaccines targeted to decrease the viral load.
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Affiliation(s)
- Christine M Rousseau
- Department of Microbiology, University of Washington, 1959 NE Pacific Street, Box 358070, Seattle, WA 98195-8070, USA.
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Cannon NA, Donlin MJ, Fan X, Aurora R, Tavis JE. Hepatitis C virus diversity and evolution in the full open-reading frame during antiviral therapy. PLoS One 2008; 3:e2123. [PMID: 18463735 PMCID: PMC2373758 DOI: 10.1371/journal.pone.0002123] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Accepted: 03/19/2008] [Indexed: 12/19/2022] Open
Abstract
Background Pegylated interferon plus ribavirin therapy for hepatitis C virus (HCV) fails in approximately half of genotype 1 patients. Treatment failure occurs either by nonresponse (minimal declines in viral titer) or relapse (robust initial responses followed by rebounds of viral titers during or after therapy). HCV is highly variable genetically. To determine if viral genetic differences contribute to the difference between response and relapse, we examined the inter-patient genetic diversity and mutation pattern in the full open reading frame HCV genotype 1a consensus sequences. Methodology/Principal Findings Pre- and post-therapy sequences were analyzed for 10 nonresponders and 10 relapsers from the Virahep-C clinical study. Pre-therapy interpatient diversity among the relapsers was higher than in the nonresponders in the viral NS2 and NS3 genes, and post-therapy diversity was higher in the relapsers for most of HCV's ten genes. Pre-therapy diversity among the relapsers was intermediate between that of the non-responders and responders to therapy. The average mutation rate was just 0.9% at the amino acid level and similar numbers of mutations occurred in the nonresponder and relapser sequences, but the mutations in NS2 of relapsers were less conservative than in nonresponders. Finally, the number and distribution of regions under positive selection was similar between the two groups, although the nonresponders had more foci of positive selection in E2. Conclusions/Significance The HCV sequences were unexpectedly stable during failed antiviral therapy, both nonresponder and relapser sequences were under selective pressure during therapy, and variation in NS2 may have contributed to the difference in response between the nonresponder and relapser groups. These data support a role for viral genetic variability in determining the outcome of anti-HCV therapy, with those sequences that are more distant from an optimal sequence being less able to resist the pressures of interferon-based therapy. Trial registration ClinicalTrials.gov NCT00038974
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Affiliation(s)
- Nathan A. Cannon
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Maureen J. Donlin
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Xiaofeng Fan
- Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Rajeev Aurora
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - John E. Tavis
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
- Saint Louis University Liver Center, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
- * E-mail:
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44
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Viral evolution and escape during primary human immunodeficiency virus-1 infection: implications for vaccine design. Curr Opin HIV AIDS 2008; 3:60-6. [DOI: 10.1097/coh.0b013e3282f233d9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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45
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Pinel-Galzi A, Rakotomalala M, Sangu E, Sorho F, Kanyeka Z, Traoré O, Sérémé D, Poulicard N, Rabenantoandro Y, Séré Y, Konaté G, Ghesquière A, Hébrard E, Fargette D. Theme and variations in the evolutionary pathways to virulence of an RNA plant virus species. PLoS Pathog 2007; 3:e180. [PMID: 18039030 PMCID: PMC2094307 DOI: 10.1371/journal.ppat.0030180] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 10/12/2007] [Indexed: 11/19/2022] Open
Abstract
The diversity of a highly variable RNA plant virus was considered to determine the range of virulence substitutions, the evolutionary pathways to virulence, and whether intraspecific diversity modulates virulence pathways and propensity. In all, 114 isolates representative of the genetic and geographic diversity of Rice yellow mottle virus (RYMV) in Africa were inoculated to several cultivars with eIF(iso)4G-mediated Rymv1-2 resistance. Altogether, 41 virulent variants generated from ten wild isolates were analyzed. Nonconservative amino acid replacements at five positions located within a stretch of 15 codons in the central region of the 79-aa-long protein VPg were associated with virulence. Virulence substitutions were fixed predominantly at codon 48 in most strains, whatever the host genetic background or the experimental conditions. There were one major and two isolate-specific mutational pathways conferring virulence at codon 48. In the prevalent mutational pathway I, arginine (AGA) was successively displaced by glycine (GGA) and glutamic acid (GAA). Substitutions in the other virulence codons were displaced when E48 was fixed. In the isolate-specific mutational pathway II, isoleucine (ATA) emerged and often later coexisted with valine (GTA). In mutational pathway III, arginine, with the specific S2/S3 strain codon usage AGG, was displaced by tryptophane (TGG). Mutational pathway I never arose in the widely spread West African S2/S3 strain because G48 was not infectious in the S2/S3 genetic context. Strain S2/S3 least frequently overcame resistance, whereas two geographically localized variants of the strain S4 had a high propensity to virulence. Codons 49 and 26 of the VPg, under diversifying selection, are candidate positions in modulating the genetic barriers to virulence. The theme and variations in the evolutionary pathways to virulence of RYMV illustrates the extent of parallel evolution within a highly variable RNA plant virus species.
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Affiliation(s)
- Agnès Pinel-Galzi
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
| | - Mbolarinosy Rakotomalala
- Centre National de la Recherche Appliquée au Développement Rural (FOFIFA), Mahajanga, Madagascar
| | - Emmanuel Sangu
- Botany Department, Dar es Salaam University, Dar es Salaam, Tanzania
| | | | - Zakaria Kanyeka
- Botany Department, Dar es Salaam University, Dar es Salaam, Tanzania
| | - Oumar Traoré
- Institut de l'Environnement et de Recherches Agricoles (INERA), Laboratoire de Biotechnologie et de Virologie Végétale, Kamboinsé, Ouagadougou, Burkina Faso
| | - Drissa Sérémé
- Institut de l'Environnement et de Recherches Agricoles (INERA), Laboratoire de Biotechnologie et de Virologie Végétale, Kamboinsé, Ouagadougou, Burkina Faso
| | - Nils Poulicard
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
| | - Yvonne Rabenantoandro
- Centre National de la Recherche Appliquée au Développement Rural (FOFIFA), Antananarivo, Madagascar
| | | | - Gnissa Konaté
- Institut de l'Environnement et de Recherches Agricoles (INERA), Laboratoire de Biotechnologie et de Virologie Végétale, Kamboinsé, Ouagadougou, Burkina Faso
| | - Alain Ghesquière
- Institut de Recherche pour le Développement (IRD), UMR GDP, Montpellier, France
| | - Eugénie Hébrard
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
| | - Denis Fargette
- Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France
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46
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Poon AFY, Kosakovsky Pond SL, Richman DD, Frost SDW. Mapping protease inhibitor resistance to human immunodeficiency virus type 1 sequence polymorphisms within patients. J Virol 2007; 81:13598-607. [PMID: 17913806 PMCID: PMC2168824 DOI: 10.1128/jvi.01570-07] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Resistance genotyping provides an important resource for the clinical management of patients infected with human immunodeficiency virus type 1 (HIV-1). However, resistance to protease (PR) inhibitors (PIs) is a complex phenotype shaped by interactions among nearly half of the residues in HIV-1 PR. Previous studies of the genetic basis of PI resistance focused on fixed substitutions among populations of HIV-1, i.e., host-specific adaptations. Consequently, they are susceptible to a high false discovery rate due to founder effects. Here, we employ sequencing "mixtures" (i.e., ambiguous base calls) as a site-specific marker of genetic variation within patients that is independent of the phylogeny. We demonstrate that the transient response to selection by PIs is manifested as an excess of nonsynonymous mixtures. Using a sample of 5,651 PR sequences isolated from both PI-naive and -treated patients, we analyze the joint distribution of mixtures and eight PIs as a Bayesian network, which distinguishes residue-residue interactions from direct associations with PIs. We find that selection for resistance is associated with the emergence of nonsynonymous mixtures in two distinct groups of codon sites clustered along the substrate cleft and distal regions of PR, respectively. Within-patient evolution at several positions is independent of PIs, including those formerly postulated to be involved in resistance. These positions are under strong positive selection in the PI-naive patient population, implying that other factors can produce spurious associations with resistance, e.g., mutational escape from the immune response.
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Affiliation(s)
- Art F Y Poon
- Department of Pathology, University of California, San Diego, La Jolla, California, USA.
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