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Salkeld J, Themistocleous Y, Barrett JR, Mitton CH, Rawlinson TA, Payne RO, Hou MM, Khozoee B, Edwards NJ, Nielsen CM, Sandoval DM, Bach FA, Nahrendorf W, Ramon RL, Baker M, Ramos-Lopez F, Folegatti PM, Quinkert D, Ellis KJ, Poulton ID, Lawrie AM, Cho JS, Nugent FL, Spence PJ, Silk SE, Draper SJ, Minassian AM. Repeat controlled human malaria infection of healthy UK adults with blood-stage Plasmodium falciparum: Safety and parasite growth dynamics. Front Immunol 2022; 13:984323. [PMID: 36072606 PMCID: PMC9444061 DOI: 10.3389/fimmu.2022.984323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
In endemic settings it is known that natural malaria immunity is gradually acquired following repeated exposures. Here we sought to assess whether similar acquisition of blood-stage malaria immunity would occur following repeated parasite exposure by controlled human malaria infection (CHMI). We report the findings of repeat homologous blood-stage Plasmodium falciparum (3D7 clone) CHMI studies VAC063C (ClinicalTrials.gov NCT03906474) and VAC063 (ClinicalTrials.gov NCT02927145). In total, 24 healthy, unvaccinated, malaria-naïve UK adult participants underwent primary CHMI followed by drug treatment. Ten of these then underwent secondary CHMI in the same manner, and then six of these underwent a final tertiary CHMI. As with primary CHMI, malaria symptoms were common following secondary and tertiary infection, however, most resolved within a few days of treatment and there were no long term sequelae or serious adverse events related to CHMI. Despite detectable induction and boosting of anti-merozoite serum IgG antibody responses following each round of CHMI, there was no clear evidence of anti-parasite immunity (manifest as reduced parasite growth in vivo) conferred by repeated challenge with the homologous parasite in the majority of volunteers. However, three volunteers showed some variation in parasite growth dynamics in vivo following repeat CHMI that were either modest or short-lived. We also observed no major differences in clinical symptoms or laboratory markers of infection across the primary, secondary and tertiary challenges. However, there was a trend to more severe pyrexia after primary CHMI and the absence of a detectable transaminitis post-treatment following secondary and tertiary infection. We hypothesize that this could represent the initial induction of clinical immunity. Repeat homologous blood-stage CHMI is thus safe and provides a model with the potential to further the understanding of naturally acquired immunity to blood-stage infection in a highly controlled setting.
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Affiliation(s)
- Jo Salkeld
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Jordan R. Barrett
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Celia H. Mitton
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Ruth O. Payne
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Mimi M. Hou
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Baktash Khozoee
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Nick J. Edwards
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Carolyn M. Nielsen
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Diana Muñoz Sandoval
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Florian A. Bach
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Wiebke Nahrendorf
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Megan Baker
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | | | - Doris Quinkert
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Ian D. Poulton
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Alison M. Lawrie
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Jee-Sun Cho
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Fay L. Nugent
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Philip J. Spence
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Sarah E. Silk
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Simon J. Draper
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Angela M. Minassian
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
- *Correspondence: Angela M. Minassian,
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Kotepui M, Kotepui KU, Milanez GD, Masangkay FR. Reduction in total leukocytes in malaria patients compared to febrile controls: A systematic review and meta-analysis. PLoS One 2020; 15:e0233913. [PMID: 32574170 PMCID: PMC7310711 DOI: 10.1371/journal.pone.0233913] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/14/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Leukocyte alterations are a common hematological alteration among malaria patients. OBJECTIVES This systematic review and meta-analysis aimed to provide data and evidence comparing alterations in total leukocyte counts in malaria patients compared to febrile/healthy subjects at baseline before treatment. A systematic review was conducted by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement for reporting systematic reviews and meta-analyses. DATA SOURCES Web of Science (ISI), Scopus, and Medline. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS All published articles reporting a total leukocyte count of patients infected with malaria, non-malaria (febrile or healthy group) at baseline before treatment before August 27, 2019, were retrieved, and data were extracted by two main reviewers independently. STUDY APPRAISAL AND SYNTHESIS METHODS We used a forest plot, heterogeneity test (Cochran's Q), and the degree of heterogeneity (I2) to test whether the included studies were heterogeneous. The quality of the included studies was determined by a quality assessment guide based on the quality assessment tool developed by the Newcastle-Ottawa Scale (NOS). Cochran's Q (Chi-square) and Moran's I2 were used to evaluate heterogeneity. Meta-regression using STATA software was conducted to find the source of heterogeneity. A funnel plot with Egger's test was used to examine the significance of publication bias among the included studies. The mean differences were estimated using a random-effects model. RESULTS Out of the 2,261 articles screened, 29 articles were included in this systematic review and meta-analysis. The heterogeneity test indicated that there was heterogeneity among the included studies with no publication bias. The meta-analysis demonstrated that the total leukocyte count was significantly lower in patients with malaria (n = 4,619) than in those without malaria (n = 10,056) (Z = 4.0, P-value < 0.00001, mean difference = -1.38, 95% CI = -2.06-(-0.71)). Leukocyte differential alterations, low lymphocyte counts (P-value <0.0001, mean difference = -1.03, 95% CI = -1.53-(-0.53)) and a high NL ratio were found in the malaria group (n = 1,579) compared to the non-malaria group (n = 4,991) (P-value <0.0001, mean difference = 0.6, 95% CI = 0.32-0.88). The subgroup analysis indicated that there was a significantly lower total leukocyte count in the malaria group (n = 3,545) than in the febrile group (n = 8,947) (Z = 1.33, P-value < 0.0001, mean difference = -1.76, 95% CI = -2.56-(-0.96)), but no significant difference was found between the malaria group (n = 1,232) and the healthy group (n = 1,679) (P-value > 0.05). LIMITATIONS As the specific diagnoses in the febrile groups were not reported in the included studies so that the results of the present study need to be carefully interpreted. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS This systematic review demonstrated that the total leukocyte count was affected by malarial infection at baseline despite the heterogeneity of the included studies. Future work must aim to understand the treatment-related total leukocyte reduction during follow-up or post-treatment outcomes in malaria-endemic settings.
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Affiliation(s)
- Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Thasala, Nakhon Si Thammarat, Thailand
| | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Thasala, Nakhon Si Thammarat, Thailand
| | - Giovanni D. Milanez
- Department of Medical Technology, Institute of Arts and Sciences, Far Eastern University, Manila, Philippines
| | - Frederick R. Masangkay
- Department of Medical Technology, Institute of Arts and Sciences, Far Eastern University, Manila, Philippines
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Abstract
Controlled human malaria infection (CHMI) entails deliberate infection with malaria parasites either by mosquito bite or by direct injection of sporozoites or parasitized erythrocytes. When required, the resulting blood-stage infection is curtailed by the administration of antimalarial drugs. Inducing a malaria infection via inoculation with infected blood was first used as a treatment (malariotherapy) for neurosyphilis in Europe and the United States in the early 1900s. More recently, CHMI has been applied to the fields of malaria vaccine and drug development, where it is used to evaluate products in well-controlled early-phase proof-of-concept clinical studies, thus facilitating progression of only the most promising candidates for further evaluation in areas where malaria is endemic. Controlled infections have also been used to immunize against malaria infection. Historically, CHMI studies have been restricted by the need for access to insectaries housing infected mosquitoes or suitable malaria-infected individuals. Evaluation of vaccine and drug candidates has been constrained in these studies by the availability of a limited number of Plasmodium falciparum isolates. Recent advances have included cryopreservation of sporozoites, the manufacture of well-characterized and genetically distinct cultured malaria cell banks for blood-stage infection, and the availability of Plasmodium vivax-specific reagents. These advances will help to accelerate malaria vaccine and drug development by making the reagents for CHMI more widely accessible and also enabling a more rigorous evaluation with multiple parasite strains and species. Here we discuss the different applications of CHMI, recent advances in the use of CHMI, and ongoing challenges for consideration.
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van Wolfswinkel ME, Langenberg MCC, Wammes LJ, Sauerwein RW, Koelewijn R, Hermsen CC, van Hellemond JJ, van Genderen PJ. Changes in total and differential leukocyte counts during the clinically silent liver phase in a controlled human malaria infection in malaria-naïve Dutch volunteers. Malar J 2017; 16:457. [PMID: 29126422 PMCID: PMC5681833 DOI: 10.1186/s12936-017-2108-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/04/2017] [Indexed: 11/25/2022] Open
Abstract
Background Both in endemic countries and in imported malaria, changes in total and differential leukocyte count during Plasmodium falciparum infection have been described. To study the exact dynamics of differential leukocyte counts and their ratios, they were monitored in a group of healthy non-immune volunteers in two separate Controlled Human Malaria Infection (CHMI) studies. Methods In two CHMI trials, CHMI-a and CHMI-b, 15 and 24 healthy malaria-naïve volunteers, respectively, were exposed to bites of infected mosquitoes, using the P. falciparum research strain NF54 and the novel clones NF135.C10 and NF166.C8. After mosquito bite exposure, twice-daily blood draws were taken to detect parasitaemia and to monitor the total and differential leukocyte counts. All subjects received a course of atovaquone–proguanil when meeting the treatment criteria. Results A total of 39 volunteers participated in the two trials. Thirty-five participants, all 15 participants in CHMI-a and 20 of the 24 volunteers in CHMI-b, developed parasitaemia. During liver stage development of the parasite, the median total leukocyte count increased from 5.5 to 6.1 × 109 leukocytes/L (p = 0.005), the median lymphocyte count from 1.9 to 2.2 (p = 0.001) and the monocyte count from 0.50 to 0.54 (p = 0.038). During the subsequent blood stage infection, significant changes in total and differential leukocyte counts lead to a leukocytopenia (nadir median 3.3 × 109 leukocytes/L, p = 0.0001), lymphocytopenia (nadir median 0.7 × 109 lymphocytes/L, p = 0.0001) and a borderline neutropenia (nadir median 1.5 × 109 neutrophils/L, p = 0.0001). The neutrophil to lymphocyte count ratio (NLCR) reached a maximum of 4.0. Significant correlations were found between parasite load and absolute lymphocyte count (p < 0.001, correlation coefficient − 0.46) and between parasite load and NLCR (p < 0.001, correlation coefficient 0.50). All parameters normalized after parasite clearance. Conclusions During the clinically silent liver phase of malaria, an increase of peripheral total leukocyte count and differential lymphocytes and monocytes occurs. This finding has not been described previously. This increase is followed by the appearance of parasites in the peripheral blood after 2–3 days, accompanied by a marked decrease in total leukocyte count, lymphocyte count and the neutrophil count and a rise of the NLCR. Electronic supplementary material The online version of this article (10.1186/s12936-017-2108-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marlies E van Wolfswinkel
- Institute for Tropical Diseases, Harbour Hospital, Rotterdam, The Netherlands. .,Department of Medical Microbiology and Infectious Diseases, Erasmus MC and Harbour Hospital, Rotterdam, The Netherlands.
| | - Marijke C C Langenberg
- Institute for Tropical Diseases, Harbour Hospital, Rotterdam, The Netherlands.,Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Linda J Wammes
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC and Harbour Hospital, Rotterdam, The Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob Koelewijn
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC and Harbour Hospital, Rotterdam, The Netherlands
| | - Cornelus C Hermsen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jaap J van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC and Harbour Hospital, Rotterdam, The Netherlands
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Taniguchi T, Md Mannoor K, Nonaka D, Toma H, Li C, Narita M, Vanisaveth V, Kano S, Takahashi M, Watanabe H. A Unique Subset of γδ T Cells Expands and Produces IL-10 in Patients with Naturally Acquired Immunity against Falciparum Malaria. Front Microbiol 2017; 8:1288. [PMID: 28769886 PMCID: PMC5515829 DOI: 10.3389/fmicb.2017.01288] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 06/27/2017] [Indexed: 01/03/2023] Open
Abstract
Although expansions in γδ T cell populations are known to occur in the peripheral blood of patients infected with Plasmodium falciparum, the role of these cells in people with naturally acquired immunity against P. falciparum who live in malaria-endemic areas is poorly understood. We used a cross-sectional survey to investigate the role of peripheral blood γδ T cells in people living in Lao People's Democratic Republic, a malaria-endemic area. We found that the proportion of non-Vγ9 γδ T cells was higher in non-hospitalized uncomplicated falciparum malaria patients (UMPs) from this region. Notably, we found that the non-Vγ9 γδ T cells in the peripheral blood of UMPs and negative controls from this region had the potential to expand and produce IL-10 and interferon-γ when cultured in the presence of IL-2 and/or crude P. falciparum antigens for 10 days. Furthermore, these cells were associated with plasma interleukin 10 (IL-10), which was elevated in UMPs. This is the first report demonstrating that, in UMPs living in a malaria-endemic area, a γδ T cell subset, the non-Vγ9 γδT cells, expands and produces IL-10. These results contribute to understanding of the mechanisms of naturally acquired immunity against P. falciparum.
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Affiliation(s)
- Tomoyo Taniguchi
- Department of Parasitology, Graduate School of Medicine, Gunma UniversityMaebashi, Japan
- Center for Medical Education, Graduate School of Medicine, Gunma UniversityMaebashi, Japan
- Immunobiology Group, Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the RyukyusNishihara, Japan
| | - Kaiissar Md Mannoor
- Department of Pathology, University of Maryland School of Medicine, BaltimoreMD, United States
| | - Daisuke Nonaka
- Department of Parasitology and Immunopathoetiology, Graduate School of Medicine, University of the RyukyusNishihara, Japan
| | - Hiromu Toma
- Department of Parasitology and Immunopathoetiology, Graduate School of Medicine, University of the RyukyusNishihara, Japan
| | - Changchun Li
- Department of Health Sciences, Trans-disciplinary Research Organization for Subtropics and Island Studies, University of the RyukyusNishihara, Japan
| | - Miwako Narita
- Laboratory of Hematology and Oncology, Graduate School of Health Sciences, Niigata UniversityNiigata, Japan
| | | | - Shigeyuki Kano
- Research Institute, National Center for Global Health and MedicineTokyo, Japan
| | - Masuhiro Takahashi
- Laboratory of Hematology and Oncology, Graduate School of Health Sciences, Niigata UniversityNiigata, Japan
| | - Hisami Watanabe
- Immunobiology Group, Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the RyukyusNishihara, Japan
- Infectious Diseases Research Center of Niigata University in Myanmar, Institute of Medicine and Dentistry, Niigata UniversityNiigata, Japan
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Early Immune Regulatory Changes in a Primary Controlled Human Plasmodium vivax Infection: CD1c + Myeloid Dendritic Cell Maturation Arrest, Induction of the Kynurenine Pathway, and Regulatory T Cell Activation. Infect Immun 2017; 85:IAI.00986-16. [PMID: 28320838 DOI: 10.1128/iai.00986-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/15/2017] [Indexed: 01/03/2023] Open
Abstract
Plasmodium vivax malaria remains a major public health problem. The requirements for acquisition of protective immunity to the species are not clear. Dendritic cells (DC) are essential for immune cell priming but also perform immune regulatory functions, along with regulatory T cells (Treg). An important function of DC involves activation of the kynurenine pathway via indoleamine 2,3-dioxygenase (IDO). Using a controlled human experimental infection study with blood-stage P. vivax, we characterized plasmacytoid DC (pDC) and myeloid DC (mDC) subset maturation, CD4+ CD25+ CD127lo Treg activation, and IDO activity. Blood samples were collected from six healthy adults preinoculation, at peak parasitemia (day 14; ∼31,400 parasites/ml), and 24 and 48 h after antimalarial treatment. CD1c+ and CD141+ mDC and pDC numbers markedly declined at peak parasitemia, while CD16+ mDC numbers appeared less affected. HLA-DR expression was selectively reduced on CD1c+ mDC, increased on CD16+ mDC, and was unaltered on pDC. Plasma IFN-γ increased significantly and was correlated with an increased kynurenine/tryptophan (KT) ratio, a measure of IDO activity. At peak parasitemia, Treg presented an activated CD4+ CD25+ CD127lo CD45RA- phenotype and upregulated TNFR2 expression. In a mixed-effects model, the KT ratio was positively associated with an increase in activated Treg. Our data demonstrate that a primary P. vivax infection exerts immune modulatory effects by impairing HLA-DR expression on CD1c+ mDC while activating CD16+ mDC. Induction of the kynurenine pathway and increased Treg activation, together with skewed mDC maturation, suggest P. vivax promotes an immunosuppressive environment, likely impairing the development of a protective host immune response.
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Immune activation and induction of memory: lessons learned from controlled human malaria infection with Plasmodium falciparum. Parasitology 2016; 143:224-35. [PMID: 26864135 DOI: 10.1017/s0031182015000761] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Controlled human malaria infections (CHMIs) are a powerful tool to assess the efficacy of drugs and/or vaccine candidates, but also to study anti-malarial immune responses at well-defined time points after infection. In this review, we discuss the insights that CHMI trials have provided into early immune activation and regulation during acute infection, and the capacity to induce and maintain immunological memory. Importantly, these studies show that a single infection is sufficient to induce long-lasting parasite-specific T- and B-cell memory responses, and suggest that blood-stage induced regulatory responses can limit inflammation both in ongoing and potentially future infections. As future perspective of investigation in CHMIs, we discuss the role of innate cell subsets, the interplay between innate and adaptive immune activation and the potential modulation of these responses after natural pre-exposure.
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Elias SC, Choudhary P, de Cassan SC, Biswas S, Collins KA, Halstead FD, Bliss CM, Ewer KJ, Hodgson SH, Duncan CJA, Hill AVS, Draper SJ. Analysis of human B-cell responses following ChAd63-MVA MSP1 and AMA1 immunization and controlled malaria infection. Immunology 2014; 141:628-44. [PMID: 24303947 PMCID: PMC3956436 DOI: 10.1111/imm.12226] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 02/07/2023] Open
Abstract
Acquisition of non-sterilizing natural immunity to Plasmodium falciparum malaria has been shown in low transmission areas following multiple exposures. However, conflicting data from endemic areas suggest that the parasite may interfere with the induction of effective B-cell responses. To date, the impact of blood-stage parasite exposure on antigen-specific B cells has not been reported following controlled human malaria infection (CHMI). Here we analysed human B-cell responses in a series of Phase I/IIa clinical trials, which include CHMI, using candidate virus-vectored vaccines encoding two blood-stage antigens: merozoite surface protein 1 (MSP1) and apical membrane antigen 1 (AMA1). Previously vaccinated volunteers show boosting of pre-existing antigen-specific memory B-cell (mBC) responses following CHMI. In contrast, unvaccinated malaria-naive control volunteers developed an mBC response against MSP1 but not AMA1. Serum IgG correlated with the mBC response after booster vaccination but this relationship was less well maintained following CHMI. A significant reduction in peripheral MSP1-specific mBC was observed at the point of diagnosis of blood-stage infection. This was coincident with a reduction in peripheral blood B-cell subsets expressing CXCR3 and elevated serum levels of interferon-γ and CXCL9, suggesting migration away from the periphery. These CHMI data confirm that mBC and antibody responses can be induced and boosted by blood-stage parasite exposure, in support of epidemiological studies on low-level parasite exposure.
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Affiliation(s)
- Sean C Elias
- The Jenner Institute, University of Oxford, Oxford, UK
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Sullivan SA, Zhu M, Bao S, Lewis CA, Ou-Yang CW, Zhang W. The role of LAT-PLCγ1 interaction in γδ T cell development and homeostasis. THE JOURNAL OF IMMUNOLOGY 2014; 192:2865-74. [PMID: 24523509 DOI: 10.4049/jimmunol.1302493] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
LAT is a transmembrane adaptor protein that is vital for integrating TCR-mediated signals to modulate T cell development, activation, and proliferation. Upon T cell activation, LAT is phosphorylated and associates with Grb2, Gads, and PLCγ1 through its four distal tyrosine residues. Mutation of one of these tyrosines, Y136, abolishes LAT binding to PLCγ1. This results in impaired TCR-mediated calcium mobilization and Erk activation. CD4 αβ T cells in LATY136F knock-in mice undergo uncontrolled expansion, resulting in a severe autoimmune syndrome. In this study, we investigated the importance of the LAT-PLCγ1 interaction in γδ T cells by crossing LATY136F mice with TCRβ(-/-) mice. Our data showed that the LATY136F mutation had no major effect on homeostasis of epithelial γδ T cells, which could be found in the skin and small intestine. Interestingly, a population of CD4(+) γδ T cells in the spleen and lymph nodes underwent continuous expansion and produced elevated amounts of IL-4, resulting in an autoimmune syndrome similar to that caused by αβ T cells in LATY136F mice. Development of these hyperproliferative γδ T cells was not dependent on MHC class II expression or CD4, and their proliferation could be suppressed, in part, by regulatory T cells. Our data indicated that a unique subset of CD4 γδ T cells can hyperproliferate in LATY136F mice and suggested that LAT-PLCγ1 signaling may function differently in various subsets of γδ T cells.
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Affiliation(s)
- Sarah A Sullivan
- Department of Immunology, Duke University Medical Center, Durham, NC 27710
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Abstract
Plasmodium falciparum malaria remains a major cause of mortality throughout the tropical world. Haematological abnormalities are considered a hallmark of malaria, bearing an impact on final outcome and representing indices of prognostic and follow-up value. These include severe anaemia, coagulation disturbances, leukocyte numerical or functional changes and spleen involvement. Anaemia involves red blood cell lysis due to parasite invasion, as well as mechanisms of intravascular haemolysis and decreased erythropoiesis. Exchange or blood transfusion is mainly recommended in the management of these patients. Haemorrhagic complications in severe malaria are relatively rare despite prominent thrombocytopenia and dysfunction in the coagulation pathway. Numerical, as well as functional changes in the white blood cell are less dramatic than other blood cell series, but still, remain a significant index of disease progression and ultimate prognosis. Finally, the role of the spleen in severe malaria is multifactorial. Care and vigilance should be taken against splenic rupture which is fatal and can occur despite appropriate antimalarial prophylaxis and treatment.
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Engwerda CR, Minigo G, Amante FH, McCarthy JS. Experimentally induced blood stage malaria infection as a tool for clinical research. Trends Parasitol 2012; 28:515-21. [PMID: 23041118 DOI: 10.1016/j.pt.2012.09.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 09/10/2012] [Accepted: 09/13/2012] [Indexed: 11/29/2022]
Abstract
A system for experimentally induced blood stage malaria infection (IBSM) with Plasmodium falciparum by direct intravenous inoculation of infected erythrocytes was developed at the Queensland Institute of Medical Research (QIMR) more than 15 years ago. Since that time, this system has been used in several studies to investigate the protective effect of vaccines, the clearance kinetics of parasites following drug treatment, and to improve understanding of the early events in blood stage infection. In this article, we will review the development of IBSM and the applications for which it is being employed. We will discuss the advantages and disadvantages of IBSM, and finish by describing some exciting new areas of research that have been made possible by this system.
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Teirlinck AC, McCall MBB, Roestenberg M, Scholzen A, Woestenenk R, de Mast Q, van der Ven AJAM, Hermsen CC, Luty AJF, Sauerwein RW. Longevity and composition of cellular immune responses following experimental Plasmodium falciparum malaria infection in humans. PLoS Pathog 2011; 7:e1002389. [PMID: 22144890 PMCID: PMC3228790 DOI: 10.1371/journal.ppat.1002389] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 10/05/2011] [Indexed: 01/09/2023] Open
Abstract
Cellular responses to Plasmodium falciparum parasites, in particular interferon-gamma (IFNγ) production, play an important role in anti-malarial immunity. However, clinical immunity to malaria develops slowly amongst naturally exposed populations, the dynamics of cellular responses in relation to exposure are difficult to study and data about the persistence of such responses are controversial. Here we assess the longevity and composition of cellular immune responses following experimental malaria infection in human volunteers. We conducted a longitudinal study of cellular immunological responses to sporozoites (PfSpz) and asexual blood-stage (PfRBC) malaria parasites in naïve human volunteers undergoing single (n = 5) or multiple (n = 10) experimental P. falciparum infections under highly controlled conditions. IFNγ and interleukin-2 (IL-2) responses following in vitro re-stimulation were measured by flow-cytometry prior to, during and more than one year post infection. We show that cellular responses to both PfSpz and PfRBC are induced and remain almost undiminished up to 14 months after even a single malaria episode. Remarkably, not only ‘adaptive’ but also ‘innate’ lymphocyte subsets contribute to the increased IFNγ response, including αβT cells, γδT cells and NK cells. Furthermore, results from depletion and autologous recombination experiments of lymphocyte subsets suggest that immunological memory for PfRBC is carried within both the αβT cells and γδT compartments. Indeed, the majority of cytokine producing T lymphocytes express an CD45RO+ CD62L- effector memory (EM) phenotype both early and late post infection. Finally, we demonstrate that malaria infection induces and maintains polyfunctional (IFNγ+IL-2+) EM responses against both PfRBC and PfSpz, previously found to be associated with protection. These data demonstrate that cellular responses can be readily induced and are long-lived following infection with P. falciparum, with a persisting contribution by not only adaptive but also (semi-)innate lymphocyte subsets. The implications hereof are positive for malaria vaccine development, but focus attention on those factors potentially inhibiting such responses in the field. A decade into the 21st century, malaria remains responsible for an intolerable global health burden and an effective vaccine is sorely needed. Compounding the many technical hurdles in developing such a vaccine, (naturally-acquired) immunity to malaria is generally perceived to be short-lived, although direct evidence from field studies is conflicting. To overcome this issue, we measured the development of immune responses against the malaria parasite Plasmodium falciparum in human volunteers undergoing experimental malaria infections for the first time, allowing a uniquely detailed analysis thereof. We found that cellular immune responses against two clinically-relevant life-stages of the parasite are not only rapidly acquired following even a single malaria infection, but also remain virtually undiminished over a year later – an unprecedented measurement. These findings refute conclusively the notion that an intrinsic defect exists in either the development or persistence of cellular immune responses against malaria. This realization, in conjunction with a growing recognition that such responses are indeed associated with clinical protection against malaria, markedly enhances the prospect of one day developing a successful vaccine. Simultaneously, however, these results re-focus attention on the question of why the development of long-lived immune responses is often inhibited under conditions of natural exposure.
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Affiliation(s)
- Anne C. Teirlinck
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Matthew B. B. McCall
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Meta Roestenberg
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Anja Scholzen
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rob Woestenenk
- Department of Laboratory Medicine, Laboratory of Hematology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Quirijn de Mast
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Andre J. A. M. van der Ven
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Cornelus C. Hermsen
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Adrian J. F. Luty
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Robert W. Sauerwein
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail:
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McCall MBB, Sauerwein RW. Interferon-γ--central mediator of protective immune responses against the pre-erythrocytic and blood stage of malaria. J Leukoc Biol 2010; 88:1131-43. [PMID: 20610802 DOI: 10.1189/jlb.0310137] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Immune responses against Plasmodium parasites, the causative organisms of malaria, are traditionally dichotomized into pre-erythrocytic and blood-stage components. Whereas the central role of cellular responses in pre-erythrocytic immunity is well established, protection against blood-stage parasites has generally been ascribed to humoral responses. A number of recent studies, however, have highlighted the existence of cellular immunity against blood-stage parasites, in particular, the prominence of IFN-γ production. Here, we have undertaken to chart the contribution of this prototypical cellular cytokine to immunity against pre-erythrocytic and blood-stage parasites. We summarize the various antiparasitic effector functions that IFN-γ serves to induce, review an array of data about its protective effects, and scrutinize evidence for any deleterious, immunopathological outcome in malaria patients. We discuss the activation and contribution of different cellular sources of IFN-γ production during malaria infection and its regulation in relation to exposure. We conclude that IFN-γ forms a central mediator of protective immune responses against pre-erythrocytic and blood-stage malaria parasites and identify a number of implications for rational malaria vaccine development.
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Affiliation(s)
- Matthew B B McCall
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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McKenzie FE, Prudhomme WA, Magill AJ, Forney JR, Permpanich B, Lucas C, Gasser RA, Wongsrichanalai C. White blood cell counts and malaria. J Infect Dis 2005; 192:323-30. [PMID: 15962228 PMCID: PMC2481386 DOI: 10.1086/431152] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Accepted: 02/17/2005] [Indexed: 11/03/2022] Open
Abstract
White blood cells (WBCs) were counted in 4697 individuals who presented to outpatient malaria clinics in Maesod, Tak Province, Thailand, and Iquitos, Peru, between 28 May and 28 August 1998 and between 17 May and 9 July 1999. At each site and in each year, WBC counts in the Plasmodium falciparum-infected patients were lower than those in the Plasmodium vivax-infected patients, which, in turn, were lower than those in the uninfected patients. In Thailand, one-sixth of the P. falciparum-infected patients had WBC counts of <4000 cells/microL. Leukopenia may confound population studies that estimate parasite densities on the basis of an assumed WBC count of 8000 cells/microL. For instance, in the present study, use of this conventional approach would have overestimated average asexual parasite densities in the P. falciparum-infected patients in Thailand by nearly one-third.
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Affiliation(s)
- F Ellis McKenzie
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland 20892, USA.
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15
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Martini F, Paglia MG, Montesano C, Enders PJ, Gentile M, Pauza CD, Gioia C, Colizzi V, Narciso P, Pucillo LP, Poccia F. V gamma 9V delta 2 T-cell anergy and complementarity-determining region 3-specific depletion during paroxysm of nonendemic malaria infection. Infect Immun 2003; 71:2945-9. [PMID: 12704176 PMCID: PMC153242 DOI: 10.1128/iai.71.5.2945-2949.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
V gamma 9V delta 2 T lymphocytes strongly respond to phosphoantigens from Plasmodium parasites. Thus, we analyzed the changes in V gamma 9V delta 2 T-cell function and repertoire during the paroxysm phase of nonendemic malaria infection. During malaria paroxysm, V gamma 9V delta 2 T cells were early activated but rapidly became anergic and finally loose J gamma 1.2 V gamma 9 complementarity-determining region 3 transcripts.
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Affiliation(s)
- Federico Martini
- Laboratory of Clinical Pathology, National Institute for Infectious Diseases Lazzaro Spallanzani I.R.C.C.S., Rome, Italy.
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Husum H, Heger T, Sundet M. Postinjury malaria: a study of trauma victims in cambodia. THE JOURNAL OF TRAUMA 2002; 52:259-66. [PMID: 11834985 DOI: 10.1097/00005373-200202000-00010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The pattern of host defense against plasmodium is comparable to the immune response to bacterial infection. Posttraumatic immunosuppression may therefore cause relapses of malaria secondary to trauma and trauma surgery in asymptomatic carriers of the parasites in endemic areas. To our knowledge this has not been validated in epidemiologic studies. METHODS Postinjury malaria was registered retrospectively in 342 land mine and war victims from malaria-endemic areas in Cambodia. The incidence rate was analyzed in terms of age, gender, preinjury endemicity, evacuation times, anatomic injury severity, systolic blood pressure at admission, blood transfusion, and duration of the first surgical intervention as independent variables. RESULTS The rate of postinjury malaria in the study patients was 33.3% (95% CI, 28.3-38.3%). Injury Severity Score (ISS) and surgical operation time were risk factors (area under the curve in receiver operating characteristic plots were 0.73 and 0.79, respectively). The impact of the other risk factors was nonsignificant. CONCLUSION Despite difficulties in diagnosing postoperative malaria in endemic areas, the study demonstrates that the rate of postinjury malaria is high. The results legitimate controlled trials of immediate postinjury chemoprophylaxis to severely injured in endemic areas. The authors recommend staged surgical operations with brief primary interventions in victims with severe injuries.
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Affiliation(s)
- Hans Husum
- Tromsoe Mine Victim Resource Center, Institute of Clinical Medicine, Tromsoe University Hospital, Tromsoe, Norway.
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Kroca M, Johansson A, Sjöstedt A, Tärnvik A. V gamma 9V delta 2 T cells in human legionellosis. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2001; 8:949-54. [PMID: 11527809 PMCID: PMC96177 DOI: 10.1128/cdli.8.5.949-954.2001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In humans, expansion of circulating Vgamma9Vdelta2 T cells seems to be a pathophysiological denominator shared by protozoan and intracellular bacterial diseases. The assumption was tested here on legionellosis, a condition conforming to the category but not yet described with respect to gammadelta T cells. Levels of Vgamma9Vdelta2 T cells in peripheral blood were measured at various intervals in 14 subjects undergoing a Pontiac fever-like disease, shown by serological investigation to be caused by Legionella micdadei. In samples obtained 4 to 6 days after the onset of the disease, the mean percentage (+/- the standard deviation) of Vgamma9Vdelta2+ T cells among CD3+ cells was 1.0% +/- 0.5%, compared to 5.0% +/- 3.9% in healthy control subjects (P < 0.001). Thereafter, a pronounced increase occurred and at 2 to 7 weeks after onset, mean peak levels were as high as approximately equal to 15%. During the next 6 months, values slowly declined, although without reaching the normal range. Percentages of gammadelta+ T cells expressing tumor necrosis factor alpha or gamma interferon in response to phorbol myristate acetate were assayed in vitro. At 14 to 16 days after the onset of disease, the expression of both cytokines was increased (P < 0.01), whereas at 5 to 7 weeks, the expression of tumor necrosis factor alpha was decreased (P < 0.05), possibly reflecting modulation of an inflammatory response. In conclusion, Pontiac fever was found to be associated with a pronounced and long-lasting expansion of Vgamma9Vdelta2 T cells, implying that the subset may also be pathophysiologically important in a mild and transient form of intracellular bacterial diseases. Surprisingly, the expansion was preceded by a depletion of circulatory Vgamma9Vdelta2 T cells. Possibly, Vgamma9Vdelta2 T cells are initially recruited to a site of infection before they expand in response to antigen and occur in high numbers in blood.
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Affiliation(s)
- M Kroca
- Department of Infectious Diseases, Umeå University Hospital, SE-901 85 Umeå, Sweden
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18
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Contamin H, Behr C, Mercereau-Puijalon O, Michel J. Plasmodium falciparumin the squirrel monkey (Saimiri sciureus): infection of non-splenectomised animals as a model for exploring clinical manifestations of malaria. Microbes Infect 2000; 2:945-54. [PMID: 10962278 DOI: 10.1016/s1286-4579(00)00401-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Plasmodium falciparum infection in humans leads to a variety of symptoms ranging from an influenza-like syndrome to life-threatening complications. Animal models are useful tools for the detailed analysis of the interaction between both parasite and host factors leading to these various clinical manifestations. In this review, examining the different clinical, parasitological and haematological parameters associated with P. falciparum infection in spleen-intact monkeys, we propose this model as a good alternative for exploring some aspects of the host-parasite relationship in malaria.
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Affiliation(s)
- H Contamin
- Laboratoire d'immunologie parasitaire et centre de primatologie, Institut Pasteur de la Guyane, Cayenne, French Guiana
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19
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Abstract
A variety of abnormalities in the number, morphology and function of blood and bone marrow cells may be found in Plasmodium falciparum and P. vivax malaria. In a non-immune individual, the nature of such abnormalities depends on the time after infection. In others it is determined by the pattern and intensity of malaria transmission in the area and the extent of host immunity. Severe anaemia may occur in children with chronic falciparum malaria and low parasitaemia as well as in patients with complicated acute falciparum malaria with high parasitaemia. However, the mechanisms underlying the anaemia in these two situations appear to be different. The possible roles of parasite products, T-cell-derived cytokines produced in response to the infection, macrophage activation and hyperplasia, macrophage-derived factors such as tumour necrosis factor-alpha, and macrophage dysfunction in the pathogenesis of the haematological abnormalities are discussed.
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Affiliation(s)
- S N Wickramasinghe
- Department of Haematology, Imperial College School of Medicine, St Mary's Campus, London, W2 1PG, UK
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20
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Waterfall M, Black A, Riley E. Gammadelta+ T cells preferentially respond to live rather than killed malaria parasites. Infect Immun 1998; 66:2393-8. [PMID: 9573139 PMCID: PMC108213 DOI: 10.1128/iai.66.5.2393-2398.1998] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/1997] [Accepted: 03/02/1998] [Indexed: 02/07/2023] Open
Abstract
We have compared the in vitro responses of peripheral blood T cells from malaria-unexposed donors to live Plasmodium falciparum schizonts, freeze-thawed schizont extracts (P. falciparum schizont extracts [PfSE]), and parasite culture supernatants. We show that the cells responding to PfSE and parasite culture supernatants are predominantly CD4+ TCR alphabeta+ while in the presence of live schizonts there is an additional activation of TCR gammadelta+ cells. Activation of TCR gammadelta+ cells in response to PfSE was seen only when irradiated autologous feeder cells or recombinant interleukin-2 (IL-2) was added to the cultures. Live schizonts but not PfSE induced significant IL-2 production in vitro in the first 5 days after stimulation, suggesting that induction of early IL-2 by live parasites may contribute to the marked activation of the TCR gammadelta+ population.
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Affiliation(s)
- M Waterfall
- Institute of Cell, Animal and Population Biology, Ashworth Laboratories, University of Edinburgh, United Kingdom
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21
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Hirunpetcharat C, Good MF. Deletion of Plasmodium berghei-specific CD4+ T cells adoptively transferred into recipient mice after challenge with homologous parasite. Proc Natl Acad Sci U S A 1998; 95:1715-20. [PMID: 9465082 PMCID: PMC19161 DOI: 10.1073/pnas.95.4.1715] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The immune response to malaria parasites includes T cell responses that reduce parasites by effector T cell responses and by providing help for antibody responses. Some parasites are more sensitive to antibody and others are more sensitive to cell-mediated immunity. We demonstrate that cultured CD4(+) T cells that produce interferon gamma and interleukin 2, but not interleukin 4, in response to stimulation with the rodent parasite Plasmodium berghei can reduce but not eliminate parasites in vivo after adoptive transfer. Although cells can persist in vivo for up to 9 months in uninfected mice, infection results in elimination of up to 99% of specific T cells in different tissues, as judged by tracking T cells labeled with the fluorescent dye 5-(and -6)-carboxyfluorescein diacetate succinimidyl ester. T cells specific for ovalbumin are unaffected. In vivo activation and division of transferred T cells per se are not responsible for deletion because T cells positive for 5-(and -6)-carboxyfluorescein diacetate succinimidyl ester divide up to six times within 7 days in uninfected mice and are not deleted. Understanding the factors responsible for parasite-mediated specific deletion of T cells would enhance our knowledge of parasite immunity.
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Affiliation(s)
- C Hirunpetcharat
- Malaria and Arbovirus Unit, The Queensland Institute of Medical Research, P.O. Royal Brisbane Hospital, Brisbane 4029, Australia
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22
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Hviid L, Kurtzhals JA, Goka BQ, Oliver-Commey JO, Nkrumah FK, Theander TG. Rapid reemergence of T cells into peripheral circulation following treatment of severe and uncomplicated Plasmodium falciparum malaria. Infect Immun 1997; 65:4090-3. [PMID: 9317012 PMCID: PMC175588 DOI: 10.1128/iai.65.10.4090-4093.1997] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Frequencies and absolute numbers of peripheral T-cell subsets were monitored closely following acute Plasmodium falciparum malaria in 22 Ghanaian children from an area of hyperendemicity for seasonal malaria transmission. The children presented with cerebral or uncomplicated malaria (CM or UM, respectively) or with severe malarial anemia. For all patients the frequencies and absolute numbers of peripheral T cells were lower than normal during the acute stage of disease. This lowering was most pronounced in the CM group and least pronounced in the UM group. Of particular interest, the CM patients showed markedly reduced frequencies of CD4+ cells, the number of which also normalized slower than in the other clinical groups. In all patients, the T-cell frequencies gradually approached normal values after the initiation of therapy, whereas the absolute numbers rapidly reverted from lower than normal to higher than normal before returning to steady-state levels. Furthermore, the initially reduced T-cell surface density of the T-cell receptor/CD3 complex, which rapidly normalized, was a general finding for all three clinical groups, suggesting a state of peripheral T-cell hyporesponsiveness during acute malaria. The data presented suggest a rapid therapy-induced reemergence of T cells that had been temporarily removed from the peripheral circulation as a consequence of the malaria attack and that the degree of the disease-induced T-cell reallocation correlates with disease severity.
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Affiliation(s)
- L Hviid
- Center for Medical Parasitology, Copenhagen University Hospital (Rigshospitalet), University of Copenhagen, Denmark.
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Rzepczyk CM, Anderson K, Stamatiou S, Townsend E, Allworth A, McCormack J, Whitby M. Gamma delta T cells: their immunobiology and role in malaria infections. Int J Parasitol 1997; 27:191-200. [PMID: 9088990 DOI: 10.1016/s0020-7519(96)00149-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The status of research on gamma delta T cells is reviewed. Recent research shows that gamma delta T cells may see antigens in an immunoglobulin-like manner and that non-peptidic substance can be antigens for these cells. Considerable advances have been made in defining the immunobiology of gamma delta T cells, with evidence for sentinel, protective and immunoregulatory roles. Research on gamma delta T cells in malaria infections suggests that gamma delta T cells are mediators of protective immunity, most probably through the production of Th1 cytokines such as TNF alpha, TNF delta and IFN gamma and that excessive production of such cytokines may contribute to pathology. Our data on the features of the peripheral blood gamma delta T cells response in humans infected with Plasmodium falciparum show that there is considerable variation between individuals in the relative expansion of gamma delta T lymphocytes following primary or secondary infection. They confirm that activation of gamma delta T cells occurs during P. falciparum infection and that activated cells can persist for many weeks after treatment. The possibility that gamma delta T cells have an immunoregulatory function in malaria infections is proposed.
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Affiliation(s)
- C M Rzepczyk
- Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research, Royal Brisbane Hospital, Herston, Australia.
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Hviid L, Kurtzhals JA, Dodoo D, Rodrigues O, Rønn A, Commey JO, Nkrumah FK, Theander TG. The gamma/delta T-cell response to Plasmodium falciparum malaria in a population in which malaria is endemic. Infect Immun 1996; 64:4359-62. [PMID: 8926112 PMCID: PMC174380 DOI: 10.1128/iai.64.10.4359-4362.1996] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Frequencies and absolute numbers of peripheral gamma/delta T cells have been reported to increase after episodes of Plasmodium falciparum malaria in adults with limited or no previous malaria exposure. In contrast, little is known about the gamma/delta T-cell response to malaria in children from areas where malaria is endemic, who bear the burden of malaria-related morbidity and mortality. We investigated the gamma/delta T-cell response in 19 Ghanaian children from an area of hyperendemic, seasonal malaria transmission. The children presented with cerebral malaria (n = 7), severe malarial anemia (n = 5), or uncomplicated malaria (n = 7) and were monitored from admission until 4 weeks later. We found no evidence of increased frequencies of gamma/delta T cells in any of the patient groups, whereas one adult expatriate studied in Ghana and three adults admitted to the hospital in Copenhagen, Denmark, all with uncomplicated, primary P. falciparum malaria, showed increased gamma/delta T-cell frequencies similar to those previously reported. All patients had lowered absolute numbers of peripheral gamma/delta T cells at admission, changing to increased numbers by days 7 to 14 and then returning to normal levels. The study raises questions regarding age and degree of previous exposure as determinants of malaria-induced gamma/delta T-cell responses.
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Affiliation(s)
- L Hviid
- Centre for Medical Parasitology at RHIMA Centre, Copenhagen University Hospital (Rigshospitalet), Denmark.
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Dick S, Waterfall M, Currie J, Maddy A, Riley E. Naive human alpha beta T cells respond to membrane-associated components of malaria-infected erythrocytes by proliferation and production of interferon-gamma. Immunology 1996; 88:412-20. [PMID: 8774359 PMCID: PMC1456345 DOI: 10.1046/j.1365-2567.1996.d01-661.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Crude extracts of Plasmodium falciparum schizont-infected erythrocytes (PfSE) induce polyclonal activation of peripheral blood T lymphocytes from naive (malaria unexposed) humans. We demonstrate that the active component of PfSE is membrane bound, soluble in sodium dodecyl sulphate (SDS) and partially heat stable, but distinct from the tumour necrosis factor (TNF)-inducing, exoantigen-like activity of schizont extracts. Malaria pigment induces little or no T-cell activation. The responding cells are predominately CD4+, CD45RO+, T-cell receptor (TCR) alpha beta+. Contrary to previous reports, expansion of the TCR gamma delta+ subset was observed in cells from only one of eight donors. Proliferating cells secrete interferon-gamma (IFN-gamma) and release large amounts of soluble interleukin-2R (sIL-2R) into the culture supernatant but produce no detectable interleukin-4 (IL-4), a phenotype typical of the T-helper (Th)1 subset of CD4+ T cells. We propose that these activated T cells may initiate the inflammatory response to malaria infection in non-immunes and may contribute to the pathology of the disease.
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Affiliation(s)
- S Dick
- Institute of Cell, Animal and Population Biology, University of Edinburgh, UK
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