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Henriques PM, Almeida GG, Rimkute I, dos Santos LI, Liechti T, Marino AP, do Vale INPC, Vasconcelos‐Santos DV, Martins‐Filho OA, Gazzinelli RT, Roederer M, Sher A, Teixeira‐Carvalho A, Jankovic D, Antonelli LRDV. Cytotoxic Signature and IFN-γ Production Dominate CD4 + T-Cell Response During Human Toxoplasmosis. Immunology 2025; 175:151-164. [PMID: 40035468 PMCID: PMC12052435 DOI: 10.1111/imm.13912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2024] [Revised: 02/10/2025] [Accepted: 02/12/2025] [Indexed: 03/05/2025] Open
Abstract
Toxoplasma gondii is a highly versatile parasite that infects most warm-blooded animals and is a major cause of retinochoroiditis and uveitis in humans. The pathophysiology of these conditions remains poorly understood. Both parasite virulence and host inflammatory response contribute to the development of ocular disease. While CD4+ T cells play a critical role in host resistance to Toxoplasma infection, their kinetics and effector functions, as well as their contribution to the clinical outcome of the infection, including ocular involvement, remain poorly understood. To address this question, we investigated the immune response during acute and convalescent toxoplasmosis and stratified patients further based on the presence or absence of ocular disease. We found that T. gondii infection leads to decreased and increased proportions of central and effector memory CD4+ T cells, respectively. Applying unsupervised analysis, distinct CD4+ T-cell subsets were determined. Among 50 clusters, 10 produced cytotoxic proteins (granzyme B and perforin) and one produced cytokines upon antigen-specific stimulation. We observed that proportions of five CD4+ T-cell clusters out of 50 were different during acute disease between T. gondii-infected patients with and without ocular lesions. Interestingly, three of the five displayed a cytotoxic signature indicating their possible involvement in ocular immunopathology. Taken together, our results reveal that during T. gondii infection, CD4+ T cells not only develop a Th1 cytokine profile, but also acquire previously unappreciated cytotoxic capacity/function. These results, while underscoring the complexity of the CD4+ T-cell response to T. gondii, suggest that specific subsets may be involved in the development of pathology and provide possible targets for therapeutic intervention.
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Affiliation(s)
- Priscilla Miranda Henriques
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
| | - Gregório Guilherme Almeida
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
| | - Inga Rimkute
- Vaccine Research Center, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Luara Isabela dos Santos
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
- Department of Basic Science, Faculty of Medical Sciences of Minas GeraisBelo HorizonteMinas GeraisBrazil
| | - Thomas Liechti
- Vaccine Research Center, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Ana Paula Marino
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
| | | | - Daniel Vitor Vasconcelos‐Santos
- Department of Ophthalmology and Otorhinolaryngology, Faculty of MedicineFederal University of Minas GeraisBelo HorizonteMinas GeraisBrazil
| | - Olindo Assis Martins‐Filho
- Integrated Research Group in Biomarkers, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
| | - Ricardo Tostes Gazzinelli
- Laboratory of Immunopathology, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
| | - Mario Roederer
- Vaccine Research Center, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Alan Sher
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Andréa Teixeira‐Carvalho
- Integrated Research Group in Biomarkers, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
| | - Dragana Jankovic
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Lis Ribeiro do Valle Antonelli
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou InstituteOswaldo Cruz Foundation‐FIOCRUZBelo HorizonteMinas GeraisBrazil
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Desale H, Tu W, Goff K, Marx PA, Herrera C, Dumonteil E. PBMC transcriptomic signatures reflect Trypanosoma cruzi strain diversity and trained immunity in chronically infected macaques. JCI Insight 2025; 10:e186003. [PMID: 39774119 PMCID: PMC11949070 DOI: 10.1172/jci.insight.186003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2024] [Accepted: 12/26/2024] [Indexed: 01/11/2025] Open
Abstract
Chagas disease is a tropical disease caused by Trypanosoma cruzi with clinical presentations ranging from asymptomatic to cardiac and/or gastrointestinal complications. The mechanisms of pathogenesis are still poorly understood, but T. cruzi strain diversity may be associated with disease progression. Therefore, we evaluated the transcriptomic response of PBMCs from macaques with natural chronic infections and tested for heterogeneity in their gene signatures. Remarkably, transcriptomic response to T. cruzi infection matched parasite strain profiles, indicating that parasite diversity is a key determinant of host response. While differences in adaptive immune responses were identified, more striking alterations of innate immune processes were detected. Thus, initial innate response to T. cruzi infection may be conditioned by parasite strain diversity, resulting in different profiles of trained immunity modulating subsequent adaptive responses, allowing parasite control or its persistence during the chronic phase. These results call for further characterization of the cross-talk between innate and adaptive immunity according to parasite diversity as well as how altered trained immunity contributes to pathogenesis, as this may lead to better treatments and vaccines.
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Affiliation(s)
- Hans Desale
- Department of Tropical Medicine and Infectious Disease, School of Public Health and Tropical Medicine, and
- Vector-Borne and Infectious Disease Research Center, Tulane University, New Orleans, Louisiana, USA
| | - Weihong Tu
- Department of Tropical Medicine and Infectious Disease, School of Public Health and Tropical Medicine, and
- Vector-Borne and Infectious Disease Research Center, Tulane University, New Orleans, Louisiana, USA
| | - Kelly Goff
- Division of Microbiology, Tulane National Primate Research Center, Tulane University, Covington, Louisiana, USA
| | - Preston A. Marx
- Department of Tropical Medicine and Infectious Disease, School of Public Health and Tropical Medicine, and
- Division of Microbiology, Tulane National Primate Research Center, Tulane University, Covington, Louisiana, USA
| | - Claudia Herrera
- Department of Tropical Medicine and Infectious Disease, School of Public Health and Tropical Medicine, and
- Vector-Borne and Infectious Disease Research Center, Tulane University, New Orleans, Louisiana, USA
| | - Eric Dumonteil
- Department of Tropical Medicine and Infectious Disease, School of Public Health and Tropical Medicine, and
- Vector-Borne and Infectious Disease Research Center, Tulane University, New Orleans, Louisiana, USA
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do Vale INPC, Almeida GG, Rimkute I, Liechti T, de Araújo FF, dos Santos LI, Henriques PM, Rocha MODC, Elói-Santos SM, Martins−Filho OA, Roederer M, Sher A, Jankovic D, Teixeira−Carvalho A, Antonelli LRDV. Signatures of CD4 + T and B cells are associated with distinct stages of chronic chagasic cardiomyopathy. Front Immunol 2024; 15:1385850. [PMID: 38726014 PMCID: PMC11079136 DOI: 10.3389/fimmu.2024.1385850] [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: 02/13/2024] [Accepted: 03/27/2024] [Indexed: 05/12/2024] Open
Abstract
Introduction Chagas disease is a neglected parasitic disease caused by Trypanosoma cruzi. While most patients are asymptomatic, around 30% develop Chronic Chagasic Cardiomyopathy (CCC). Methods Here, we employed high-dimensional flow cytometry to analyze CD4+ T and B cell compartments in patients during the chronic phase of Chagas disease, presenting the asymptomatic and mild or moderate/severe cardiac clinical forms. Results Effector CD27-CD4+ T cells were expanded in both CCC groups, and only mild CCC patients showed higher frequencies of effector memory and T follicular helper (Tfh) cells than healthy donors (CTL) and asymptomatic patients. Unsupervised analysis confirmed these findings and further revealed the expansion of a specific subpopulation composed of Tfh, transitional, and central memory CD4+ T cells bearing a phenotype associated with strong activation, differentiation, and exhaustion in patients with mild but not moderate/severe CCC. In contrast, patients with mild and moderate/severe CCC had lower frequencies of CD4+ T cells expressing lower levels of activation markers, suggesting resting status, than CTL. Regarding the B cell compartment, no alterations were found in naïve CD21-, memory cells expressing IgM or IgD, marginal zone, and plasma cells in patients with Chagas disease. However, expansion of class-switched activated and atypical memory B cells was observed in all clinical forms, and more substantially in mild CCC patients. Discussion Taken together, our results showed that T. cruzi infection triggers changes in CD4+ T and B cell compartments that are more pronounced in the mild CCC clinical form, suggesting an orchestrated cellular communication during Chagas disease. Conclusion Overall, these findings reinforce the heterogeneity and complexity of the immune response in patients with chronic Chagas disease and may provide new insights into disease pathology and potential markers to guide clinical decisions.
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Affiliation(s)
- Isabela Natália Pascoal Campos do Vale
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
- Integrated Research Group in Biomarkers, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
| | - Gregório Guilherme Almeida
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
| | - Inga Rimkute
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Thomas Liechti
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Fernanda Fortes de Araújo
- Integrated Research Group in Biomarkers, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
| | - Luara Isabela dos Santos
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
- Departament of Basic Science, Faculty of Medical Sciences of Minas Gerais, Belo Horizonte, Brazil
| | - Priscilla Miranda Henriques
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
| | - Manoel Otávio da Costa Rocha
- Department of Clinical Medicine, Postgraduate Program in Infectious Diseases and Tropical Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Silvana Maria Elói-Santos
- Integrated Research Group in Biomarkers, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
- Department of Complementary Propedeutics, Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Olindo Assis Martins−Filho
- Integrated Research Group in Biomarkers, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
| | - Mario Roederer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Alan Sher
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Dragana Jankovic
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Andréa Teixeira−Carvalho
- Integrated Research Group in Biomarkers, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
| | - Lis Ribeiro do Valle Antonelli
- Biology and Immunology of Infectious and Parasitic Diseases Group, René Rachou Institute, Oswaldo Cruz Foundation-FIOCRUZ, Belo Horizonte, Brazil
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Araujo Furlan CL, Boccardo S, Rodriguez C, Mary VS, Gimenez CMS, Robson SC, Gruppi A, Montes CL, Acosta Rodríguez EV. CD39 expression by regulatory T cells participates in CD8+ T cell suppression during experimental Trypanosoma cruzi infection. PLoS Pathog 2024; 20:e1012191. [PMID: 38683845 PMCID: PMC11081507 DOI: 10.1371/journal.ppat.1012191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 05/09/2024] [Accepted: 04/12/2024] [Indexed: 05/02/2024] Open
Abstract
An imbalance between suppressor and effector immune responses may preclude cure in chronic parasitic diseases. In the case of Trypanosoma cruzi infection, specialized regulatory Foxp3+ T (Treg) cells suppress protective type-1 effector responses. Herein, we investigated the kinetics and underlying mechanisms behind the regulation of protective parasite-specific CD8+ T cell immunity during acute T. cruzi infection. Using the DEREG mouse model, we found that Treg cells play a role during the initial stages after T. cruzi infection, restraining the magnitude of CD8+ T cell responses and parasite control. Early Treg cell depletion increased the frequencies of polyfunctional short-lived, effector T cell subsets, without affecting memory precursor cell formation or the expression of activation, exhaustion and functional markers. In addition, Treg cell depletion during early infection minimally affected the antigen-presenting cell response but it boosted CD4+ T cell responses before the development of anti-parasite effector CD8+ T cell immunity. Crucially, the absence of CD39 expression on Treg cells significantly bolstered effector parasite-specific CD8+ T cell responses, preventing increased parasite replication in T. cruzi infected mice adoptively transferred with Treg cells. Our work underscores the crucial role of Treg cells in regulating protective anti-parasite immunity and provides evidence that CD39 expression by Treg cells represents a key immunomodulatory mechanism in this infection model.
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Affiliation(s)
- Cintia L. Araujo Furlan
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
| | - Santiago Boccardo
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
| | - Constanza Rodriguez
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
| | - Verónica S. Mary
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
| | - Camila M. S. Gimenez
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
| | - Simon C. Robson
- Center for Inflammation Research, Department of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Adriana Gruppi
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
| | - Carolina L. Montes
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
| | - Eva V. Acosta Rodríguez
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CONICET, Córdoba, Argentina
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Jones KM, Zhan B, Ernste KJ, Villar MJ, Bisht N, Nguyen D, Chang LY, Poveda C, Robinson GJ, Trivedi AJ, Hofferek CJ, Decker WK, Konduri V. Immunomodulatory proteins from hookworms reduce cardiac inflammation and modulate regulatory responses in a mouse model of chronic Trypanosoma cruzi infection. FRONTIERS IN PARASITOLOGY 2023; 2:1244604. [PMID: 38239430 PMCID: PMC10795693 DOI: 10.3389/fpara.2023.1244604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/19/2023] [Indexed: 01/22/2024]
Abstract
Introduction Hookworms are parasitic helminths that secrete a variety of proteins that induce anti-inflammatory immune responses, stimulating increased CD4 + Foxp3+ regulatory T cells and IL-10 production. Hookworm-derived recombinant proteins AIP-1 and AIP-2 have been shown to reduce inflammation in mouse models of inflammatory bowel disease and inflammatory airway disease by inducing CD4+Foxp3+ cells and IL-10 production. In contrast, chronic infection with the protozoal parasite Trypanosoma cruzi, the causative agent of Chagas disease, leads to chronic inflammation in tissues. Persistence of the parasites in tissues drives chronic low-grade inflammation, with increased infiltration of inflammatory cells into the heart, accompanied by increased production of inflammatory cytokines. There are no current antiparasitic drugs that effectively reduce or prevent chronic myocarditis caused by the onset of Chagas disease, thus new therapies are urgently needed. Therefore, the impact of AIP-1 and AIP-2 on myocarditis was investigated in a mouse model of chronic T. cruzi infection. Methods Female BALB/c mice infected with bioluminescent T. cruzi H1 strain trypomastigotes for 70 days were treated once daily for 7 days with 1mg/kg AIP-1 or AIP-2 protein by intraperitoneal injection. Control mice were left untreated or treated once daily for 14 days with 25mg/kg aspirin in drinking water. At 84 days of infection, splenocytes, cardiac tissue and serum were collected for evaluation. Results Treatment with both AIP-1 and AIP-2 proteins significantly reduced cardiac cellular infiltration, and reduced cardiac levels of IFNγ, IL-6 and IL-2. AIP-2 treatment reduced cardiac expression of COX-2. Further, while incubation with AIP-1 and AIP-2 proteins did not induce a significant upregulation of an immunoregulatory phenotype in dendritic cells (DC), there was a modest upregulation of CD11c +CD11b+MHCII+SIRPα+ expression, suggesting a regulatory phenotype. Ex-vivo stimulation of splenocytes from the treatment groups with AIP-1 loaded DC induced reduced levels of cytotoxic and pro-inflammatory T cells, stimulation with AIP-2 loaded DC specifically induced enhanced levels of CD4+CD25+Foxp3+ regulatory T cells among treatment groups. Discussion All in vivo and in vitro results demonstrate that hookworm-derived AIP-1 and AIP-2 proteins reduce T. cruzi induced cardiac inflammation, possibly through multiple anti-inflammatory mechanisms.
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Affiliation(s)
- Kathryn M. Jones
- National School of Tropical Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Hospital Center for Vaccine Development, Houston, TX, United States
| | - Bin Zhan
- National School of Tropical Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Hospital Center for Vaccine Development, Houston, TX, United States
| | - Keenan J. Ernste
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
| | - Maria Jose Villar
- National School of Tropical Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Hospital Center for Vaccine Development, Houston, TX, United States
| | - Nalini Bisht
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
| | - Duc Nguyen
- Center for Comparative Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Li-Yen Chang
- Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Cristina Poveda
- National School of Tropical Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Hospital Center for Vaccine Development, Houston, TX, United States
| | - Gonteria J. Robinson
- Molecular & Human Genetics Department, Baylor College of Medicine, Houston, TX, United States
| | - Akshar J. Trivedi
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
| | - Colby J. Hofferek
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
| | - William K. Decker
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
- Dan L. Duncan Cancer, Baylor College of Medicine, Houston, TX, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, United States
| | - Vanaja Konduri
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States
- Dan L. Duncan Cancer, Baylor College of Medicine, Houston, TX, United States
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Araujo Furlan CL, Boccardo S, Rodriguez C, Robson SC, Gruppi A, Montes CL, Acosta Rodríguez EV. CD39 expression by regulatory T cells drives CD8+ T cell suppression during experimental Trypanosoma cruzi infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.14.557792. [PMID: 37745571 PMCID: PMC10515944 DOI: 10.1101/2023.09.14.557792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
An imbalance between suppressor and effector immune responses may preclude cure in chronic parasitic diseases. In the case of Trypanosoma cruzi infection, specialized regulatory Foxp3+ T (Treg) cells suppress protective type-1 effector responses. Herein, we investigated the kinetics and underlying mechanisms behind the regulation of protective parasite-specific CD8+ T cell immunity during acute T. cruzi infection. Using the DEREG mouse model, we found that Treg cells play a critical role during the initial stages after T. cruzi infection, subsequently influencing CD8+ T cells. Early Treg cell depletion increased the frequencies of polyfunctional short-lived, effector T cell subsets, without affecting memory precursor cell formation or the expression of activation markers. In addition, Treg cell depletion during early infection minimally affected the antigen-presenting cell response but it boosted CD4+ T cell responses before the development of anti-parasite effector CD8+ T cell responses. Crucially, the absence of CD39 expression on Treg cells significantly bolstered effector parasite-specific CD8+ T cell responses, leading to improved parasite control during T. cruzi infection. Our work underscores the crucial role of Treg cells in regulating protective anti-parasite immunity and provides evidence that CD39 expression by Treg cells represents a key immunomodulatory mechanism in this infection model.
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