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Dinges SS, Amini K, Notarangelo LD, Delmonte OM. Primary and secondary defects of the thymus. Immunol Rev 2024; 322:178-211. [PMID: 38228406 PMCID: PMC10950553 DOI: 10.1111/imr.13306] [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] [Indexed: 01/18/2024]
Abstract
The thymus is the primary site of T-cell development, enabling generation, and selection of a diverse repertoire of T cells that recognize non-self, whilst remaining tolerant to self- antigens. Severe congenital disorders of thymic development (athymia) can be fatal if left untreated due to infections, and thymic tissue implantation is the only cure. While newborn screening for severe combined immune deficiency has allowed improved detection at birth of congenital athymia, thymic disorders acquired later in life are still underrecognized and assessing the quality of thymic function in such conditions remains a challenge. The thymus is sensitive to injury elicited from a variety of endogenous and exogenous factors, and its self-renewal capacity decreases with age. Secondary and age-related forms of thymic dysfunction may lead to an increased risk of infections, malignancy, and autoimmunity. Promising results have been obtained in preclinical models and clinical trials upon administration of soluble factors promoting thymic regeneration, but to date no therapy is approved for clinical use. In this review we provide a background on thymus development, function, and age-related involution. We discuss disease mechanisms, diagnostic, and therapeutic approaches for primary and secondary thymic defects.
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Affiliation(s)
- Sarah S. Dinges
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Pediatric Respiratory Medicine, Immunology and Critical Care Medicine, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Kayla Amini
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Luigi D. Notarangelo
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ottavia M. Delmonte
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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2
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Savino W, Durães J, Maldonado-Galdeano C, Perdigon G, Mendes-da-Cruz DA, Cuervo P. Thymus, undernutrition, and infection: Approaching cellular and molecular interactions. Front Nutr 2022; 9:948488. [PMID: 36225882 PMCID: PMC9549110 DOI: 10.3389/fnut.2022.948488] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
Undernutrition remains a major issue in global health. Low protein-energy consumption, results in stunting, wasting and/or underweight, three deleterious forms of malnutrition that affect roughly 200 million children under the age of five years. Undernutrition compromises the immune system with the generation of various degrees of immunodeficiency, which in turn, renders undernourished individuals more sensitive to acute infections. The severity of various infectious diseases including visceral leishmaniasis (VL), influenza, and tuberculosis is associated with undernutrition. Immunosuppression resulting from protein-energy undernutrition severely impacts primary and secondary lymphoid organs involved in the response to related pathogens. The thymus—a primary lymphoid organ responsible for the generation of T lymphocytes—is particularly compromised by both undernutrition and infectious diseases. In this respect, we will discuss herein various intrathymic cellular and molecular interactions seen in undernutrition alone or in combination with acute infections. Many examples illustrated in studies on humans and experimental animals clearly revealed that protein-related undernutrition causes thymic atrophy, with cortical thymocyte depletion. Moreover, the non-lymphoid microenvironmental compartment of the organ undergoes important changes in thymic epithelial cells, including their secretory products such as hormones and extracellular matrix proteins. Of note, deficiencies in vitamins and trace elements also induce thymic atrophy. Interestingly, among the molecular interactions involved in the control of undernutrition-induced thymic atrophy is a hormonal imbalance with a rise in glucocorticoids and a decrease in leptin serum levels. Undernutrition also yields a negative impact of acute infections upon the thymus, frequently with the intrathymic detection of pathogens or their antigens. For instance, undernourished mice infected with Leishmania infantum (that causes VL) undergo drastic thymic atrophy, with significant reduction in thymocyte numbers, and decreased levels of intrathymic chemokines and cytokines, indicating that both lymphoid and microenvironmental compartments of the organ are affected. Lastly, recent data revealed that some probiotic bacteria or probiotic fermented milks improve the thymus status in a model of malnutrition, thus raising a new field for investigation, namely the thymus-gut connection, indicating that probiotics can be envisioned as a further adjuvant therapy in the control of thymic changes in undernutrition accompanied or not by infection.
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Affiliation(s)
- Wilson Savino
- Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Brazilian National Institute of Science and Technology on Neuroimmunomodulation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- *Correspondence: Wilson Savino, ,
| | - Jonathan Durães
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Laboratory on Leishmaniasis Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Carolina Maldonado-Galdeano
- Laboratory of Immunology, Reference Center for Lactobacilli Centro de Referencia para Lactobacilos-Consejo Nacional de Investigaciones Científicas y Técnicas (CERELA-CONICET), San Miguel de Tucumán, Argentina
- Laboratory of Immunology, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucumán, San Miguel de Tucumán, Argentina
| | - Gabriela Perdigon
- Laboratory of Immunology, Reference Center for Lactobacilli Centro de Referencia para Lactobacilos-Consejo Nacional de Investigaciones Científicas y Técnicas (CERELA-CONICET), San Miguel de Tucumán, Argentina
- Laboratory of Immunology, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucumán, San Miguel de Tucumán, Argentina
| | - Daniella Arêas Mendes-da-Cruz
- Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Brazilian National Institute of Science and Technology on Neuroimmunomodulation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, United Kingdom
| | - Patricia Cuervo
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Laboratory on Leishmaniasis Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
- Patricia Cuervo, ,
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3
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Luo M, Xu L, Qian Z, Sun X. Infection-Associated Thymic Atrophy. Front Immunol 2021; 12:652538. [PMID: 34113341 PMCID: PMC8186317 DOI: 10.3389/fimmu.2021.652538] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/07/2021] [Indexed: 12/17/2022] Open
Abstract
The thymus is a vital organ of the immune system that plays an essential role in thymocyte development and maturation. Thymic atrophy occurs with age (physiological thymic atrophy) or as a result of viral, bacterial, parasitic or fungal infection (pathological thymic atrophy). Thymic atrophy directly results in loss of thymocytes and/or destruction of the thymic architecture, and indirectly leads to a decrease in naïve T cells and limited T cell receptor diversity. Thus, it is important to recognize the causes and mechanisms that induce thymic atrophy. In this review, we highlight current progress in infection-associated pathogenic thymic atrophy and discuss its possible mechanisms. In addition, we discuss whether extracellular vesicles/exosomes could be potential carriers of pathogenic substances to the thymus, and potential drugs for the treatment of thymic atrophy. Having acknowledged that most current research is limited to serological aspects, we look forward to the possibility of extending future work regarding the impact of neural modulation on thymic atrophy.
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Affiliation(s)
- Mingli Luo
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Lingxin Xu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Zhengyu Qian
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Xi Sun
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
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4
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Liu Z, Su DM, Yu ZL, Wu F, Liu RF, Luo SQ, Lv ZY, Zeng X, Sun X, Wu ZD. Soluble antigens from the neurotropic pathogen Angiostrongylus cantonensis directly induce thymus atrophy in a mouse model. Oncotarget 2018; 8:48575-48590. [PMID: 28548945 PMCID: PMC5564709 DOI: 10.18632/oncotarget.17836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/02/2017] [Indexed: 11/25/2022] Open
Abstract
The nematode Angiostrongylus cantonensis (A.C.) is a neurotropic pathogen; stage-III larva invade the human (non-permissive host) central nervous system (CNS) to cause eosinophilic meningitis or meningoencephalitis accompanied by immunosuppression. In an A.C.-infectedmouse (another non-permissive host) model, CNS damage-associated T cell immune deficiency and severe inflammation were proposed to result from activation of the hypothalamic-pituitary-adrenal (HPA) axis. However, glucocorticoids are anti-inflammatory agents. Additionally, while defects in thymic stromal/epithelial cells (TECs) are the major reason for thymic atrophy, TECs do not express the glucocorticoid receptor. Therefore, activation of the HPA axis cannot fully explain the thymic atrophy and inflammation. Using an A.C.-infected mouse model, we found that A.C.-infected mice developed severe thymic atrophy with dramatic impairments in thymocytes and TECs, particularly cortical TECs, which harbor CD4+CD8+ double-positive thymocytes. The impairments resulted from soluble antigens (sAgs) from A.C. in the thymuses of infected mice, as intrathymic injection of these sAgs into live mice and the addition of these sAgs to thymic cell culture resulted in thymic atrophy and cellular apoptosis, respectively. Therefore, in addition to an indirect effect on thymocytes through the HPA axis, our study reveals a novel mechanism by which A.C. infection in non-permissive hosts directly induces defects in both thymocytes and TECs via soluble antigens.
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Affiliation(s)
- Zhen Liu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
| | - Dong-Ming Su
- Institute for Molecular Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Zi-Long Yu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
| | - Feng Wu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
| | - Rui-Feng Liu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Shi-Qi Luo
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
| | - Zhi-Yue Lv
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
| | - Xin Zeng
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
| | - Xi Sun
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
| | - Zhong-Dao Wu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control, Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Diseases-Vectors Control, Guangzhou, China
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5
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Camacho E, Niño-Vega GA. Paracoccidioides Spp.: Virulence Factors and Immune-Evasion Strategies. Mediators Inflamm 2017; 2017:5313691. [PMID: 28553014 PMCID: PMC5434249 DOI: 10.1155/2017/5313691] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/01/2017] [Accepted: 02/21/2017] [Indexed: 12/21/2022] Open
Abstract
Paracoccidioides spp. are dimorphic fungal pathogens responsible for one of the most relevant systemic mycoses in Latin America, paracoccidioidomycosis (PCM). Their exact ecological niche remains unknown; however, they have been isolated from soil samples and armadillos (Dasypus novemcinctus), which have been proposed as animal reservoir for these fungi. Human infection occurs by inhalation of conidia or mycelia fragments and is mostly associated with immunocompetent hosts inhabiting and/or working in endemic rural areas. In this review focusing on the pathogen perspective, we will discuss some of the microbial attributes and molecular mechanisms that enable Paracoccidioides spp. to tolerate, adapt, and ultimately avoid the host immune response, establishing infection.
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Affiliation(s)
- Emma Camacho
- Department of Molecular Microbiology and Immunobiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Gustavo A. Niño-Vega
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, GTO, Mexico
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6
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Alves da Costa T, Di Gangi R, Thomé R, Barreto Felisbino M, Pires Bonfanti A, Lumi Watanabe Ishikawa L, Sartori A, Burger E, Verinaud L. Severe Changes in Thymic Microenvironment in a Chronic Experimental Model of Paracoccidioidomycosis. PLoS One 2016; 11:e0164745. [PMID: 27736987 PMCID: PMC5063316 DOI: 10.1371/journal.pone.0164745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/29/2016] [Indexed: 12/26/2022] Open
Abstract
T cell maturation takes place within the thymus, a primary lymphoid organ that is commonly targeted during infections. Previous studies showed that acute infection with Paracoccidioides brasiliensis (Pb), the causative agent of paracoccidioidomycosis (PCM), promotes thymic atrophy that is associated with the presence of yeast cells in the organ. However, as human PCM is a chronic infection, it is imperative to investigate the consequences of Pb infection over the thymic structure and function in chronic infection. In this sense, we developed a new experimental model where Pb yeast cells are injected through the intraperitoneal route and mice are evaluated over 120 days of infection. Thymuses were analyzed in chronically infected mice and we found that the thymus underwent extensive morphological alterations and severe infiltration of P. brasiliensis yeast cells. Further analyses showed an altered phenotype and function of thymocytes that are commonly found in peripheral mature T lymphocytes. We also observed activation of the NLRP3 inflammasome in the thymus. Our data provide new information on the severe changes observed in the thymic microenvironment in a model of PCM that more closely mimics the human infection.
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Affiliation(s)
- Thiago Alves da Costa
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Rosária Di Gangi
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Rodolfo Thomé
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Marina Barreto Felisbino
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Amanda Pires Bonfanti
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Larissa Lumi Watanabe Ishikawa
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Univ. Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Alexandrina Sartori
- Department of Microbiology and Immunology, Institute of Biosciences of Botucatu, Univ. Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Eva Burger
- Department of Microbiology and Immunology, Institute of Biomedical Sciences, Federal University of Alfenas (UNIFAL-MG), Alfenas, Minas Gerais, Brazil
| | - Liana Verinaud
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
- * E-mail:
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7
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Morrot A, Villar SR, González FB, Pérez AR. Evasion and Immuno-Endocrine Regulation in Parasite Infection: Two Sides of the Same Coin in Chagas Disease? Front Microbiol 2016; 7:704. [PMID: 27242726 PMCID: PMC4876113 DOI: 10.3389/fmicb.2016.00704] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/28/2016] [Indexed: 12/16/2022] Open
Abstract
Chagas disease is a serious illness caused by the protozoan parasite Trypanosoma cruzi. Nearly 30% of chronically infected people develop cardiac, digestive, or mixed alterations, suggesting a broad range of host-parasite interactions that finally impact upon chronic disease outcome. The ability of T. cruzi to persist and cause pathology seems to depend on diverse factors like T. cruzi strains, the infective load and the route of infection, presence of virulence factors, the parasite capacity to avoid protective immune response, the strength and type of host defense mechanisms and the genetic background of the host. The host-parasite interaction is subject to a constant neuro-endocrine regulation that is thought to influence the adaptive immune system, and as the infection proceeds it can lead to a broad range of outcomes, ranging from pathogen elimination to its continued persistence in the host. In this context, T. cruzi evasion strategies and host defense mechanisms can be envisioned as two sides of the same coin, influencing parasite persistence and different outcomes observed in Chagas disease. Understanding how T. cruzi evade host's innate and adaptive immune response will provide important clues to better dissect mechanisms underlying the pathophysiology of Chagas disease.
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Affiliation(s)
- Alexandre Morrot
- Institute of Microbiology, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Silvina R Villar
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
| | - Florencia B González
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
| | - Ana R Pérez
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
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8
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Di Gangi R, Alves da Costa T, Thomé R, Peron G, Burger E, Verinaud L. Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs. BMC Infect Dis 2016; 16:209. [PMID: 27189089 PMCID: PMC4869377 DOI: 10.1186/s12879-016-1561-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 05/10/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it. METHODS In this paper, we show that acute infection of BALB/c mice with P. brasiliensis virulent isolate (Pb18) might cause alterations in the thymic environment as well as the prohibitive TCR-expressing T cells in the spleens. RESULTS After seven days of infection, we found yeast cells on the thymic stroma, the thymic epithelial cells (TEC) were altered regarding their spatial-orientation and inflammatory mediators gene expression was increased. Likewise, thymocytes (differentiating T cells) presented higher migratory ability in ex vivo experiments. Notwithstanding, P. brasiliensis-infected mice showed an increased frequency of prohibitive TCR-expressing T cells in the spleens, suggesting that the selection processes that occur in the thymus may be compromised during the acute infection. CONCLUSION In this paper, for the first time, we show that acute infection with Paracoccidioides brasiliensis yeast cells promotes thymic alterations leading to a defective repertoire of peripheral T cells. The data presented here may represent new mechanisms by which P. brasiliensis subverts the immune response towards the chronic infection observed in humans.
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Affiliation(s)
- Rosaria Di Gangi
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas, Rua Monteiro Lobato, 255, Cidade Universitária, SP, Brazil
| | - Thiago Alves da Costa
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas, Rua Monteiro Lobato, 255, Cidade Universitária, SP, Brazil
| | - Rodolfo Thomé
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas, Rua Monteiro Lobato, 255, Cidade Universitária, SP, Brazil
| | - Gabriela Peron
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas, Rua Monteiro Lobato, 255, Cidade Universitária, SP, Brazil
| | - Eva Burger
- Instituto de Ciências Biomédicas, Universidade Federal de Alfenas, Alfenas, MG, Brazil
| | - Liana Verinaud
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas, Rua Monteiro Lobato, 255, Cidade Universitária, SP, Brazil.
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9
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Immune Evasion Strategies of Trypanosoma cruzi. J Immunol Res 2015; 2015:178947. [PMID: 26240832 PMCID: PMC4512591 DOI: 10.1155/2015/178947] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 12/31/2014] [Indexed: 01/03/2023] Open
Abstract
Microbes have evolved a diverse range of strategies to subvert the host immune system. The protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease, provides a good example of such adaptations. This parasite targets a broad spectrum of host tissues including both peripheral and central lymphoid tissues. Rapid colonization of the host gives rise to a systemic acute response which the parasite must overcome. The parasite in fact undermines both innate and adaptive immunity. It interferes with the antigen presenting function of dendritic cells via an action on host sialic acid-binding Ig-like lectin receptors. These receptors also induce suppression of CD4(+) T cells responses, and we presented evidence that the sialylation of parasite-derived mucins is required for the inhibitory effects on CD4 T cells. In this review we highlight the major mechanisms used by Trypanosoma cruzi to overcome host immunity and discuss the role of parasite colonization of the central thymic lymphoid tissue in chronic disease.
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10
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Tolerance has its limits: how the thymus copes with infection. Trends Immunol 2013; 34:502-10. [PMID: 23871487 DOI: 10.1016/j.it.2013.06.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/25/2013] [Accepted: 06/17/2013] [Indexed: 01/11/2023]
Abstract
The thymus is required for T cell differentiation; a process that depends on which antigens are encountered by thymocytes, the environment surrounding the differentiating cells, and the thymic architecture. These features are altered by local infection of the thymus and by the inflammatory mediators that accompany systemic infection. Although once believed to be an immune privileged site, it is now known that antimicrobial responses are recruited to the thymus. Resolving infection in the thymus is important because chronic persistence of microbes impairs the differentiation of pathogen-specific T cells and diminishes resistance to infection. Understanding how these mechanisms contribute to disease susceptibility, particularly in infants with developing T cell repertoires, requires further investigation.
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11
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Nobrega C, Nunes-Alves C, Cerqueira-Rodrigues B, Roque S, Barreira-Silva P, Behar SM, Correia-Neves M. T cells home to the thymus and control infection. THE JOURNAL OF IMMUNOLOGY 2013; 190:1646-58. [PMID: 23315077 DOI: 10.4049/jimmunol.1202412] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The thymus is a target of multiple pathogens. How the immune system responds to thymic infection is largely unknown. Despite being considered an immune-privileged organ, we detect a mycobacteria-specific T cell response in the thymus following dissemination of Mycobacterium avium or Mycobacterium tuberculosis. This response includes proinflammatory cytokine production by mycobacteria-specific CD4(+) and CD8(+) T cells, which stimulates infected cells and controls bacterial growth in the thymus. Importantly, the responding T cells are mature peripheral T cells that recirculate back to the thymus. The recruitment of these cells is associated with an increased expression of Th1 chemokines and an enrichment of CXCR3(+) mycobacteria-specific T cells in the thymus. Finally, we demonstrate it is the mature T cells that home to the thymus that most efficiently control mycobacterial infection. Although the presence of mature T cells in the thymus has been recognized for some time, to our knowledge, these data are the first to show that T cell recirculation from the periphery to the thymus is a mechanism that allows the immune system to respond to thymic infection. Maintaining a functional thymic environment is essential to maintain T cell differentiation and prevent the emergence of central tolerance to the invading pathogens.
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Affiliation(s)
- Claudia Nobrega
- Life and Health Sciences Research Institute, School of Health Sciences, University of Minho, 4710-057 Braga, Portugal
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12
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Gameiro J, Nagib P, Verinaud L. The thymus microenvironment in regulating thymocyte differentiation. Cell Adh Migr 2010; 4:382-90. [PMID: 20418658 DOI: 10.4161/cam.4.3.11789] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The thymus plays a crucial role in the development of T lymphocytes by providing an inductive microenvironment in which committed progenitors undergo proliferation, T-cell receptor gene rearrangements and thymocyte differentiate into mature T cells. The thymus microenvironment forms a complex network of interaction that comprises non lymphoid cells (e.g., thymic epithelial cells, TEC), cytokines, chemokines, extracellular matrix elements (ECM), matrix metalloproteinases and other soluble proteins. The thymic epithelial meshwork is the major component of the thymic microenvironment, both morphologically and phenotypically limiting heterogeneous regions in thymic lobules and fulfilling an important role during specific stages of T-cell maturation. The process starts when bone marrow-derived lymphocyte precursors arrive at the outer cortical region of the thymic gland and begin to mature into functional T lymphocytes that will finally exit the thymus and populate the peripheral lymphoid organs. During their journey inside the thymus, thymocytes must interact with stromal cells (and their soluble products) and extracellular matrix proteins to receive appropriate signals for survival, proliferation and differentiation. The crucial components of the thymus microenvironment, and their complex interactions during the T-cell maturation process are summarized here with the objective of contributing to a better understanding of the function of the thymus, as well as assisting in the search for new therapeutic approaches to improve the immune response in various pathological conditions.
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Affiliation(s)
- Jacy Gameiro
- Department of Parasitology, Microbiology and Immunology, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
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Abstract
Infectious disease immunology has largely focused on the effector immune response, changes in the blood and peripheral lymphoid organs of infected individuals, and vaccine development. Studies of the thymus in infected individuals have been neglected, although this is progressively changing. The thymus is a primary lymphoid organ, able to generate mature T cells that eventually colonize secondary lymphoid organs, and is therefore essential for peripheral T cell renewal. Recent data show that normal thymocyte development and export can be altered as a result of an infectious disease. One common feature is the severe atrophy of the infected organ, mainly due to the apoptosis-related depletion of immature CD4+CD8+ thymocytes. Additionally, thymocyte proliferation is frequently diminished. The microenvironmental compartment of the thymus is also affected, particularly in acute infectious diseases, with a densification of the epithelial network and an increase in the deposition of extracellular matrix. In the murine model of Chagas disease, intrathymic chemokine production is also enhanced, and thymocytes from Trypanosoma cruzi-infected mice exhibit greater numbers of cell migration-related receptors for chemokines and extracellular matrix, as well as increased migratory responses to the corresponding ligands. This profile is correlated with the appearance of potentially autoreactive thymus-derived immature CD4+CD8+ T cells in peripheral organs of infected animals. A variety of infectious agents—including viruses, protozoa, and fungi—invade the thymus, raising the hypothesis of the generation of central immunological tolerance for at least some of the infectious agent-derived antigens. It seems clear that the thymus is targeted in a variety of infections, and that such targeting may have consequences on the behavior of peripheral T lymphocytes. In this context, thymus-centered immunotherapeutic approaches potentially represent a new tool for the treatment of severe infectious diseases.
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Affiliation(s)
- Wilson Savino
- Laboratory on Thymus Research, Department of Immunology, Oswaldo Cruz Institute, Inserm-Fiocruz Associated Laboratory of Immunology, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil.
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Souto PCS, Brito VN, Gameiro J, da Cruz-Höfling MA, Verinaud L. Programmed cell death in thymus during experimental paracoccidioidomycosis. Med Microbiol Immunol 2003; 192:225-9. [PMID: 12687355 DOI: 10.1007/s00430-003-0180-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2002] [Indexed: 01/09/2023]
Abstract
Many works have shown that immunosuppressive effects induced by systemic mycosis can be related to primary lymphoid organ damage. Previous studies in our laboratory showed that Paracoccidioides brasiliensis was able to invade the thymus, inducing a severe atrophy with significant reduction of cortical area along with a loss of cortico-medullary boundary. The objective of the present study was to investigate whether thymic atrophy is caused by programmed cell death (PCD) and to examine the ultrastructural characteristics of the thymus in experimentally infected BALB/c mice. The results revealed an eightfold increase in the apoptotic index occurring by day 5 post infection, i.e., during early stages of the infection, shown by immunohistochemistry. In addition, typical cell alterations of autophagic PCD were observed by transmission electron microscopy. Taken together, these results reinforce the idea that thymic alterations may be involved in the immunosuppressive phenomenon frequently associated with paracoccidioidomycotic infection.
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Affiliation(s)
- Paula C S Souto
- Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Cidade Universitária Zeferino Vaz s/n, Caixa Postal 6109, 13083-970 Campinas-SP, Brazil.
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