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Preite NW, Borges BM, Kaminski VDL, Ayupe MC, Gonçalves LM, dos Santos BV, Fonseca DLM, Filgueiras IS, Salgado CL, Muxel SM, Cabral-Marques O, da Fonseca DM, Loures FV, Calich VLG. Blocking the CTLA-4 and PD-1 pathways during pulmonary paracoccidioidomycosis improves immunity, reduces disease severity, and increases the survival of infected mice. Front Immunol 2024; 15:1347318. [PMID: 38500881 PMCID: PMC10945025 DOI: 10.3389/fimmu.2024.1347318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/14/2024] [Indexed: 03/20/2024] Open
Abstract
Immune checkpoint pathways, i.e., coinhibitory pathways expressed as feedback following immune activation, are crucial for controlling an excessive immune response. Cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) are the central classical checkpoint inhibitory (CPI) molecules used for the control of neoplasms and some infectious diseases, including some fungal infections. As the immunosuppression of severe paracoccidioidomycosis (PCM), a chronic granulomatous fungal disease, was shown to be associated with the expression of coinhibitory molecules, we hypothesized that the inhibition of CTLA-4 and PD-1 could have a beneficial effect on pulmonary PCM. To this end, C57BL/6 mice were infected with Paracoccidioides brasiliensis yeasts and treated with monoclonal antibodies (mAbs) α-CTLA-4, α-PD-1, control IgG, or PBS. We verified that blockade of CTLA-4 and PD-1 reduced the fungal load in the lungs and fungal dissemination to the liver and spleen and decreased the size of pulmonary lesions, resulting in increased survival of mice. Compared with PBS-treated infected mice, significantly increased levels of many pro- and anti-inflammatory cytokines were observed in the lungs of α-CTLA-4-treated mice, but a drastic reduction in the liver was observed following PD-1 blockade. In the lungs of α-CPI and IgG-treated mice, there were no changes in the frequency of inflammatory leukocytes, but a significant reduction in the total number of these cells was observed. Compared with PBS-treated controls, α-CPI- and IgG-treated mice exhibited reduced pulmonary infiltration of several myeloid cell subpopulations and decreased expression of costimulatory molecules. In addition, a decreased number of CD4+ and CD8+ T cells but sustained numbers of Th1, Th2, and Th17 T cells were detected. An expressive reduction in several Treg subpopulations and their maturation and suppressive molecules, in addition to reduced numbers of Treg, TCD4+, and TCD8+ cells expressing costimulatory and coinhibitory molecules of immunity, were also detected. The novel cellular and humoral profiles established in the lungs of α-CTLA-4 and α-PD-1-treated mice but not in control IgG-treated mice were more efficient at controlling fungal growth and dissemination without causing increased tissue pathology due to excessive inflammation. This is the first study demonstrating the efficacy of CPI blockade in the treatment of pulmonary PCM, and further studies combining the use of immunotherapy with antifungal drugs are encouraged.
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Affiliation(s)
| | | | | | - Marina Caçador Ayupe
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Leonardo Mandu Gonçalves
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | | | | | - Igor Salerno Filgueiras
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Caio Loureiro Salgado
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Sandra Marcia Muxel
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Otavio Cabral-Marques
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
- Department of Medicine, Division of Molecular Medicine, University of São Paulo School of Medicine (USP), São Paulo, Brazil
- Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo (USP), São Paulo, Brazil
- Network of Immunity in Infection, Malignancy, Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), São Paulo, Brazil
| | - Denise Morais da Fonseca
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Flávio Vieira Loures
- Institute of Science and Technology, Federal University of São Paulo, São Paulo, Brazil
| | - Vera Lúcia Garcia Calich
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
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Preite NW, Kaminski VDL, Borges BM, Calich VLG, Loures FV. Myeloid-derived suppressor cells are associated with impaired Th1 and Th17 responses and severe pulmonary paracoccidioidomycosis which is reversed by anti-Gr1 therapy. Front Immunol 2023; 14:1039244. [PMID: 36776848 PMCID: PMC9909482 DOI: 10.3389/fimmu.2023.1039244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/10/2023] [Indexed: 01/27/2023] Open
Abstract
Previous studies on paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in Latin America, revealed that host immunity is tightly regulated by several suppressive mechanisms mediated by tolerogenic plasmacytoid dendritic cells, the enzyme 2,3 indoleamine dioxygenase (IDO-1), and regulatory T-cells (Tregs). IDO-1 orchestrates local and systemic immunosuppressive effects through the recruitment and activation of myeloid-derived suppressor cells (MDSCs), a heterogeneous population of myeloid cells possessing a potent ability to suppress T-cell responses. However, the involvement of MDSCs in PCM remains uninvestigated. The presence, phenotype, and immunosuppressive activity of MDSCs were evaluated at 96 h, 2 weeks, and 8 weeks of pulmonary infection in C57BL/6 mice. Disease severity and immune responses were assessed in MDSC-depleted and nondepleted mice using an anti-Gr1 antibody. Both monocytic-like MDSCs (M-MDSCs) and polymorphonuclear-like MDSCs (PMN-MDSCs) massively infiltrated the lungs during Paracoccidioides brasiliensis infection. Partial reduction of MDSC frequency led to a robust Th1/Th17 lymphocyte response, resulting in regressive disease with a reduced fungal burden on target organs, diminishing lung pathology, and reducing mortality ratio compared with control IgG2b-treated mice. The suppressive activity of MDSCs on CD4 and CD8 T-lymphocytes and Th1/Th17 cells was also demonstrated in vitro using coculture experiments. Conversely, adoptive transfer of MDSCs to recipient P. brasiliensis-infected mice resulted in a more severe disease. Taken together, our data showed that the increased influx of MDSCs into the lungs was linked to more severe disease and impaired Th1 and Th17 protective responses. However, protective immunity was rescued by anti-Gr1 treatment, resulting in a less severe disease and controlled tissue pathology. In conclusion, MDSCs have emerged as potential target cells for the adjuvant therapy of PCM.
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Affiliation(s)
- Nycolas Willian Preite
- Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, São Paulo, Brazil
| | - Valéria de Lima Kaminski
- Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, São Paulo, Brazil
| | - Bruno Montanari Borges
- Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, São Paulo, Brazil
| | - Vera Lúcia Garcia Calich
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Flávio Vieira Loures
- Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, São Paulo, Brazil,*Correspondence: Flávio Vieira Loures,
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Xu J, Xiao N, Zhou D, Xie L. Disease tolerance: a protective mechanism of lung infections. Front Cell Infect Microbiol 2023; 13:1037850. [PMID: 37207185 PMCID: PMC10189053 DOI: 10.3389/fcimb.2023.1037850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 03/30/2023] [Indexed: 05/21/2023] Open
Abstract
Resistance and tolerance are two important strategies employed by the host immune response to defend against pathogens. Multidrug-resistant bacteria affect the resistance mechanisms involved in pathogen clearance. Disease tolerance, defined as the ability to reduce the negative impact of infection on the host, might be a new research direction for the treatment of infections. The lungs are highly susceptible to infections and thus are important for understanding host tolerance and its precise mechanisms. This review focuses on the factors that induce lung disease tolerance, cell and molecular mechanisms involved in tissue damage control, and the relationship between disease tolerance and sepsis immunoparalysis. Understanding the exact mechanism of lung disease tolerance could allow better assessment of the immune status of patients and provide new ideas for the treatment of infections.
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Affiliation(s)
- Jianqiao Xu
- College of Pulmonary & Critical Care Medicine, 8th Medical Center, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese PLA, Beijing, China
| | - Nan Xiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
- *Correspondence: Dongsheng Zhou, ; Lixin Xie,
| | - Lixin Xie
- College of Pulmonary & Critical Care Medicine, 8th Medical Center, Chinese PLA General Hospital, Beijing, China
- Medical School of Chinese PLA, Beijing, China
- *Correspondence: Dongsheng Zhou, ; Lixin Xie,
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Sachdeva G, Das A. Communication between immune system and mycobiota impacts health and disease. PROCEEDINGS OF THE INDIAN NATIONAL SCIENCE ACADEMY 2022. [PMCID: PMC9218050 DOI: 10.1007/s43538-022-00082-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gunjan Sachdeva
- Department of Biotechnology, Delhi Technological University, Delhi, India
| | - Asmita Das
- Department of Biotechnology, Delhi Technological University, Delhi, India
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de Araújo EF, Loures FV, Preite NW, Feriotti C, Galdino NA, Costa TA, Calich VLG. AhR Ligands Modulate the Differentiation of Innate Lymphoid Cells and T Helper Cell Subsets That Control the Severity of a Pulmonary Fungal Infection. Front Immunol 2021; 12:630938. [PMID: 33936043 PMCID: PMC8085362 DOI: 10.3389/fimmu.2021.630938] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/30/2021] [Indexed: 11/13/2022] Open
Abstract
In agreement with other fungal infections, immunoprotection in pulmonary paracoccidioidomycosis (PCM) is mediated by Th1/Th17 cells whereas disease progression by prevalent Th2/Th9 immunity. Treg cells play a dual role, suppressing immunity but also controlling excessive tissue inflammation. Our recent studies have demonstrated that the enzyme indoleamine 2,3 dioxygenase (IDO) and the transcription factor aryl hydrocarbon receptor (AhR) play an important role in the immunoregulation of PCM. To further evaluate the immunomodulatory activity of AhR in this fungal infection, Paracoccidioides brasiliensis infected mice were treated with two different AhR agonists, L-Kynurenin (L-Kyn) or 6-formylindole [3,2-b] carbazole (FICZ), and one AhR specific antagonist (CH223191). The disease severity and immune response of treated and untreated mice were assessed 96 hours and 2 weeks after infection. Some similar effects on host response were shared by FICZ and L-Kyn, such as the reduced fungal loads, decreased numbers of CD11c+ lung myeloid cells expressing activation markers (IA, CD40, CD80, CD86), and early increased expression of IDO and AhR. In contrast, the AhR antagonist CH223191 induced increased fungal loads, increased number of pulmonary CD11c+ leukocytes expressing activation markers, and a reduction in AhR and IDO production. While FICZ treatment promoted large increases in ILC3, L-Kyn and CH223191 significantly reduced this cell population. Each of these AhR ligands induced a characteristic adaptive immunity. The large expansion of FICZ-induced myeloid, lymphoid, and plasmacytoid dendritic cells (DCs) led to the increased expansion of all CD4+ T cell subpopulations (Th1, Th2, Th17, Th22, and Treg), but with a clear predominance of Th17 and Th22 subsets. On the other hand, L-Kyn, that preferentially activated plasmacytoid DCs, reduced Th1/Th22 development but caused a robust expansion of Treg cells. The AhR antagonist CH223191 induced a preferential expansion of myeloid DCs, reduced the number of Th1, Th22, and Treg cells, but increased Th17 differentiation. In conclusion, the present study showed that the pathogen loads and the immune response in pulmonary PCM can be modulated by AhR ligands. However, further studies are needed to define the possible use of these compounds as adjuvant therapy for this fungal infection.
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Affiliation(s)
- Eliseu F de Araújo
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Flávio V Loures
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Nycolas W Preite
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Cláudia Feriotti
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Nayane Al Galdino
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Tânia A Costa
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Vera L G Calich
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Pulmonary paracoccidioidomycosis in AhR deficient hosts is severe and associated with defective Treg and Th22 responses. Sci Rep 2020; 10:11312. [PMID: 32647342 PMCID: PMC7347857 DOI: 10.1038/s41598-020-68322-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/11/2020] [Indexed: 12/20/2022] Open
Abstract
AhR is a ligand-activated transcription factor that plays an important role in the innate and adaptive immune responses. In infection models, it has been associated with host responses that promote or inhibit disease progression. In pulmonary paracoccidioidomycosis, a primary fungal infection endemic in Latin America, immune protection is mediated by Th1/Th17 cells and disease severity with predominant Th2/Th9/Treg responses. Because of its important role at epithelial barriers, we evaluate the role of AhR in the outcome of a pulmonary model of paracoccidioidomycosis. AhR−/− mice show increased fungal burdens, enhanced tissue pathology and mortality. During the infection, AhR−/− mice have more pulmonary myeloid cells with activated phenotype and reduced numbers expressing indoleamine 2,3 dioxygenase 1. AhR-deficient lungs have altered production of cytokines and reduced numbers of innate lymphoid cells (NK, ILC3 and NCR IL-22). The lungs of AhR−/− mice showed increased presence Th17 cells concomitant with reduced numbers of Th1, Th22 and Foxp3+ Treg cells. Furthermore, treatment of infected WT mice with an AhR-specific antagonist (CH223191) reproduced the main findings obtained in AhR−/− mice. Collectively our data demonstrate that in pulmonary paracoccidioidomycosis AhR controls fungal burden and excessive tissue inflammation and is a possible target for antifungal therapy.
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Yang D, Li T, Li Y, Zhang S, Li W, Liang H, Xing Z, Du L, He J, Kuang C, Yang Q. H 2S suppresses indoleamine 2, 3-dioxygenase 1 and exhibits immunotherapeutic efficacy in murine hepatocellular carcinoma. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:88. [PMID: 30777103 PMCID: PMC6380069 DOI: 10.1186/s13046-019-1083-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/06/2019] [Indexed: 12/16/2022]
Abstract
Background Over-expression and over-activation of immunosuppressive enzyme indoleamine 2, 3 -dioxygenase 1 (IDO1) is a key mechanism of cancer immune escape. However, the regulation of IDO1 has not been fully studied. The relation between hydrogen sulfide (H2S) and IDO1 is unclear. Methods The influences of endogenous and exogenous H2S on the expression of IDO1, iNOS and NF-κB and STAT3 signaling proteins were investigated using qPCR or western blot, and the production of nitric oxide (NO) was analyzed by nitrate/nitrite assay in Cse−/− mice and MCF-7 and SGC-7901 cells. The effect of H2S on IDO1 activity was investigated by HPLC and in-vitro enzymatic assay. The effect of H2S on tryptophan metabolism was tested by luciferase reporter assay in MCF-7 and SGC-7901 cells. The correlation between H2S-generating enzyme CSE and IDO1 was investigated by immunostaining and heatmaps analysis in clinical specimens and tissue arrays of hepatocellular carcinoma (HCC) patients. The immunotherapeutic effects of H2S on H22 HCC-bearing mice were investigated. Results Using Cse−/− mice, we found that H2S deficiency increased IDO1 expression and activity, stimulated NF-κB and STAT3 pathways and decreased the expression of NO-generating enzyme Inos. Using IDO1-expressing MCF-7 and SGC-7901 cells, we found that exogenous H2S inhibited IDO1 expression by blocking STAT3 and NF-κB pathways, and decreased IDO1 activity via H2S/NO crosstalk, and combinedly decreased the tryptophan metabolism. The negative correlation between H2S-generating enzyme CSE and IDO1 was further validated in clinical specimens and tissue arrays of HCC patients. Additionally, H2S donors effectively restricted the tumor development in H22 HCC-bearing mice via downregulating IDO1 expression, inducing T-effector cells and inhibiting MDSCs. Conclusions Thus, H2S, as a novel negative regulator of IDO1, shows encouraging antitumor immunotherapeutic effects and represents a novel therapeutic target in cancer therapy. Electronic supplementary material The online version of this article (10.1186/s13046-019-1083-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dan Yang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Tianqi Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Yinlong Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Shengnan Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Weirui Li
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Heng Liang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Zikang Xing
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Lisha Du
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Jinchao He
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Chunxiang Kuang
- Department of Chemistry, Tongji University, Siping Road 1239, Shanghai, 200092, China
| | - Qing Yang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China.
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Galdino NAL, Loures FV, de Araújo EF, da Costa TA, Preite NW, Calich VLG. Depletion of regulatory T cells in ongoing paracoccidioidomycosis rescues protective Th1/Th17 immunity and prevents fatal disease outcome. Sci Rep 2018; 8:16544. [PMID: 30410119 PMCID: PMC6224548 DOI: 10.1038/s41598-018-35037-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/25/2018] [Indexed: 12/24/2022] Open
Abstract
In human paracoccidioidomycosis (PCM), a primary fungal infection typically diagnosed when the disease is already established, regulatory T cells (Treg) cells are associated with disease severity. Experimental studies in pulmonary PCM confirmed the detrimental role of these cells, but in most studies, Tregs were depleted prior to or early during infection. These facts led us to study the effects of Treg cell depletion using a model of ongoing PCM. Therefore, Treg cell depletion was achieved by treatment of transgenic C57BL/6DTR/eGFP (DEREG) mice with diphtheria toxin (DT) after 3 weeks of intratracheal infection with 1 × 106 Paracoccidioides brasiliensis yeasts. At weeks 6 and 10 post-infection, DT-treated DEREG mice showed a reduced number of Treg cells associated with decreased fungal burdens in the lungs, liver and spleen, reduced tissue pathology and mortality. Additionally, an increased influx of activated CD4+ and CD8+ T cells into the lungs and elevated production of Th1/Th17 cytokines was observed in DT-treated mice. Altogether, our data demonstrate for the first time that Treg cell depletion in ongoing PCM rescues infected hosts from progressive and potentially fatal PCM; furthermore, our data indicate that controlling Treg cells could be explored as a novel immunotherapeutic procedure.
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Affiliation(s)
- Nayane A L Galdino
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Flávio V Loures
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, SP, Brazil
| | - Eliseu F de Araújo
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Tania A da Costa
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Nycolas W Preite
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Vera Lúcia G Calich
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil.
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Abstract
This review addresses the role of regulatory T cells (Tregs), which are essential for maintaining peripheral tolerance and controlling pathogen immunity, in the host response against Paracoccidioides brasiliensis, a primary fungal pathogen. A brief introduction on the general features of Treg cells summarizes their main functions, subpopulations, mechanisms of suppression and plasticity. The main aspects of immunity in the diverse forms of the P. brasiliensis infection are presented, as are the few extant studies on the relevance of Treg cells in the control of severity of the human disease. Finally, the influence of Toll-like receptors, Dectin-1, NOD-like receptor P3 (NLRP3), Myeloid differentiation factor-88 (MyD88), as well as the enzyme indoleamine 2,3 dioxygenase (IDO) on the expansion and function of Treg cells in a murine model of pulmonary paracoccidioidomycosis (PCM) is also discussed. It is demonstrated that some of these components are involved in the negative control of Treg cell expansion, whereas others positively trigger the proliferation and activity of these cells. Finally, the studies here summarized highlight the dual role of Treg cells in PCM, which can be protective by controlling excessive immunity and tissue pathology but also deleterious by inhibiting the anti-fungal immunity necessary to control fungal growth and dissemination.
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Affiliation(s)
- Vera L G Calich
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP) , São Paulo , Brazil
| | - Ronei L Mamoni
- Department of Morphology and Basic Pathology, Faculty of Medicine of Jundiai (FMJ) , Jundiai , Brazil.,Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP) , São Paulo , Brazil
| | - Flávio V Loures
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP) , São Paulo , Brazil.,Institute of Science and Technology (ICT), Federal University of São Paulo (UNIFESP) at São José dos Campos , São Paulo , Brazil
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