1
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Sarkar R, Shaaz M, Sehrawat S. Myeloid derived suppressor cells potentiate virus-specific memory CD8 + T cell response. Microbes Infect 2024; 26:105277. [PMID: 38103861 DOI: 10.1016/j.micinf.2023.105277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 11/03/2023] [Accepted: 12/12/2023] [Indexed: 12/19/2023]
Abstract
How therapeutically administered myeloid derived suppressor cells (MDSCs) modulate differentiation of virus-specific CD8+ T cell was investigated. In vitro generated MDSCs from bone marrow precursors inhibited the expansion of stimulated CD8+ T cells but the effector cells in the recipients of MDSCs showed preferential memory transition during Influenza A virus (IAV) or an α- (Herpes Simplex Virus) as well as a γ- (murine herpesvirus 68) herpesvirus infection. Memory CD8+ T cells thus generated constituted a heterogenous population with a large fraction showing effector memory (CD62LloCCR7-) phenotype. Such cells could be efficiently recalled in the rechallenged animals and controlled the secondary infection better. Memory potentiating effects of MDSCs occurred irrespective of the clonality of the responding CD8+ T cells as well as the nature of infecting viruses. Compared to the MDSCs recipients, effector cells of MDSCs recipients showed higher expression of molecules known to drive cellular survival (IL-7R, Bcl2) and memory formation (Tcf7, Id3, eomesodermin). Therapeutically administered MDSCs not only mitigated the tissue damaging response during a resolving IAV infection but also promoted the differentiation of functional memory CD8+ T cells. Therefore, MDSCs therapy could be useful in managing virus-induced immunopathological reactions without compromising immunological memory.
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Affiliation(s)
- Roman Sarkar
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar Knowledge City PO Manauli, Mohali 140306, Punjab, India
| | - Mohammad Shaaz
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar Knowledge City PO Manauli, Mohali 140306, Punjab, India
| | - Sharvan Sehrawat
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar Knowledge City PO Manauli, Mohali 140306, Punjab, India.
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2
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Mulik S, Berber E, Sehrawat S, Rouse BT. Controlling viral inflammatory lesions by rebalancing immune response patterns. Front Immunol 2023; 14:1257192. [PMID: 37671156 PMCID: PMC10475736 DOI: 10.3389/fimmu.2023.1257192] [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: 07/12/2023] [Accepted: 08/07/2023] [Indexed: 09/07/2023] Open
Abstract
In this review, we discuss a variety of immune modulating approaches that could be used to counteract tissue-damaging viral immunoinflammatory lesions which typify many chronic viral infections. We make the point that in several viral infections the lesions can be largely the result of one or more aspects of the host response mediating the cell and tissue damage rather than the virus itself being directly responsible. However, within the reactive inflammatory lesions along with the pro-inflammatory participants there are also other aspects of the host response that may be acting to constrain the activity of the damaging components and are contributing to resolution. This scenario should provide the prospect of rebalancing the contributions of different host responses and hence diminish or even fully control the virus-induced lesions. We identify several aspects of the host reactions that influence the pattern of immune responsiveness and describe approaches that have been used successfully, mainly in model systems, to modulate the activity of damaging participants and which has led to lesion control. We emphasize examples where such therapies are, or could be, translated for practical use in the clinic to control inflammatory lesions caused by viral infections.
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Affiliation(s)
- Sachin Mulik
- Center for Biomedical Research, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Engin Berber
- Infection Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Sharvan Sehrawat
- Indian Institute of Science Education and Research, Department of Biological Sciences, Mohali, Punjab, India
| | - Barry Tyrrell Rouse
- College of Veterinary Medicine, University of Tennessee, Knoxville, TN, United States
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3
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Dhawan M, Rabaan AA, Alwarthan S, Alhajri M, Halwani MA, Alshengeti A, Najim MA, Alwashmi ASS, Alshehri AA, Alshamrani SA, AlShehail BM, Garout M, Al-Abdulhadi S, Al-Ahmed SH, Thakur N, Verma G. Regulatory T Cells (Tregs) and COVID-19: Unveiling the Mechanisms, and Therapeutic Potentialities with a Special Focus on Long COVID. Vaccines (Basel) 2023; 11:vaccines11030699. [PMID: 36992283 DOI: 10.3390/vaccines11030699] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 03/31/2023] Open
Abstract
The COVID-19 pandemic has caused havoc all around the world. The causative agent of COVID-19 is the novel form of the coronavirus (CoV) named SARS-CoV-2, which results in immune system disruption, increased inflammation, and acute respiratory distress syndrome (ARDS). T cells have been important components of the immune system, which decide the fate of the COVID-19 disease. Recent studies have reported an important subset of T cells known as regulatory T cells (Tregs), which possess immunosuppressive and immunoregulatory properties and play a crucial role in the prognosis of COVID-19 disease. Recent studies have shown that COVID-19 patients have considerably fewer Tregs than the general population. Such a decrement may have an impact on COVID-19 patients in a number of ways, including diminishing the effect of inflammatory inhibition, creating an inequality in the Treg/Th17 percentage, and raising the chance of respiratory failure. Having fewer Tregs may enhance the likelihood of long COVID development in addition to contributing to the disease's poor prognosis. Additionally, tissue-resident Tregs provide tissue repair in addition to immunosuppressive and immunoregulatory activities, which may aid in the recovery of COVID-19 patients. The severity of the illness is also linked to abnormalities in the Tregs' phenotype, such as reduced expression of FoxP3 and other immunosuppressive cytokines, including IL-10 and TGF-beta. Hence, in this review, we summarize the immunosuppressive mechanisms and their possible roles in the prognosis of COVID-19 disease. Furthermore, the perturbations in Tregs have been associated with disease severity. The roles of Tregs are also explained in the long COVID. This review also discusses the potential therapeutic roles of Tregs in the management of patients with COVID-19.
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Affiliation(s)
- Manish Dhawan
- Department of Microbiology, Punjab Agricultural University, Ludhiana 141004, India
- Trafford College, Altrincham, Manchester WA14 5PQ, UK
| | - Ali A Rabaan
- Molecular Diagnostic Laboratory, Johns Hopkins Aramco Healthcare, Dhahran 31311, Saudi Arabia
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
- Department of Public Health and Nutrition, The University of Haripur, Haripur 22610, Pakistan
| | - Sara Alwarthan
- Department of Internal Medicine, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia
| | - Mashael Alhajri
- Department of Internal Medicine, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 34212, Saudi Arabia
| | - Muhammad A Halwani
- Department of Medical Microbiology, Faculty of Medicine, Al Baha University, Al Baha 4781, Saudi Arabia
| | - Amer Alshengeti
- Department of Pediatrics, College of Medicine, Taibah University, Al-Madinah 41491, Saudi Arabia
- Department of Infection Prevention and Control, Prince Mohammad Bin Abdulaziz Hospital, National Guard Health Affairs, Al-Madinah 41491, Saudi Arabia
| | - Mustafa A Najim
- Department of Medical Laboratories Technology, College of Applied Medical Sciences, Taibah University, Al-Madinah 41411, Saudi Arabia
| | - Ameen S S Alwashmi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia
| | - Ahmad A Alshehri
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Najran University, Najran 61441, Saudi Arabia
| | - Saleh A Alshamrani
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Najran University, Najran 61441, Saudi Arabia
| | - Bashayer M AlShehail
- Pharmacy Practice Department, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Mohammed Garout
- Department of Community Medicine and Health Care for Pilgrims, Faculty of Medicine, Umm Al-Qura University, Makkah 21955, Saudi Arabia
| | - Saleh Al-Abdulhadi
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Riyadh 11942, Saudi Arabia
- Dr. Saleh Office for Medical Genetic and Genetic Counseling Services, The House of Expertise, Prince Sattam Bin Abdulaziz University, Dammam 32411, Saudi Arabia
| | - Shamsah H Al-Ahmed
- Specialty Paediatric Medicine, Qatif Central Hospital, Qatif 32654, Saudi Arabia
| | - Nanamika Thakur
- University Institute of Biotechnology, Department of Biotechnology, Chandigarh University, Mohali 140413, India
| | - Geetika Verma
- Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
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4
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Sarkar R, Mathew A, Sehrawat S. Myeloid-Derived Suppressor Cells Confer Infectious Tolerance to Dampen Virus-Induced Tissue Immunoinflammation. THE JOURNAL OF IMMUNOLOGY 2019; 203:1325-1337. [DOI: 10.4049/jimmunol.1900142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 06/24/2019] [Indexed: 11/19/2022]
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5
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Rajasagi NK, Rouse BT. Application of our understanding of pathogenesis of herpetic stromal keratitis for novel therapy. Microbes Infect 2018; 20:526-530. [PMID: 29329934 DOI: 10.1016/j.micinf.2017.12.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 12/31/2022]
Abstract
HSV-1 ocular infection can cause herpes stromal keratitis (SK), an immunopathological lesion. Frequent recurrences can lead to progressive corneal scaring which can result in vision impairment if left untreated. Currently, the acute and epithelial forms of SK are usually controlled using anti-viral drugs. However, chronic forms of SK which are inflammatory in nature, require the addition of a topical corticosteroid to the anti-viral treatment regimen. In this review, we highlight the essential events involved in SK pathogenesis which can be targeted for improved therapy. We also examine some approaches which can be combined with the current treatments to effectively control SK.
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Affiliation(s)
- Naveen K Rajasagi
- Biomedical & Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN, 37996-0845, United States
| | - Barry T Rouse
- Biomedical & Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN, 37996-0845, United States.
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6
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Sehrawat S, Rouse BT. Interplay of Regulatory T Cell and Th17 Cells during Infectious Diseases in Humans and Animals. Front Immunol 2017; 8:341. [PMID: 28421070 PMCID: PMC5377923 DOI: 10.3389/fimmu.2017.00341] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/09/2017] [Indexed: 12/14/2022] Open
Abstract
It is now clear that the outcome of an inflammatory process caused by infections depends on the balance of responses by several components of the immune system. Of particular relevance is the interplay between regulatory T cells (Tregs) and CD4+ T cells that produce IL-17 (Th17 cells) during immunoinflammatory events. In addition to discussing studies done in mice to highlight some unresolved issues in the biology of these cells, we emphasize the need to include outbred animals and humans in analyses. Achieving a balance between Treg and Th17 cells responses represents a powerful approach to control events during immunity and immunopathology.
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Affiliation(s)
- Sharvan Sehrawat
- Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Barry T Rouse
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN, USA
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7
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Zhang J, Liu H, Wei B. Immune response of T cells during herpes simplex virus type 1 (HSV-1) infection. J Zhejiang Univ Sci B 2017; 18:277-288. [PMID: 28378566 PMCID: PMC5394093 DOI: 10.1631/jzus.b1600460] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/07/2017] [Indexed: 12/14/2022]
Abstract
Herpes simplex virus type 1 (HSV-1), a neurotropic member of the alphaherpes virus family, is among the most prevalent and successful human pathogens. HSV-1 can cause serious diseases at every stage of life including fatal disseminated disease in newborns, cold sores, eye disease, and fatal encephalitis in adults. HSV-1 infection can trigger rapid immune responses, and efficient inhibition and clearance of HSV-1 infection rely on both the innate and adaptive immune responses of the host. Multiple strategies have been used to restrict host innate immune responses by HSV-1 to facilitate its infection in host cells. The adaptive immunity of the host plays an important role in inhibiting HSV-1 infections. The activation and regulation of T cells are the important aspects of the adaptive immunity. They play a crucial role in host-mediated immunity and are important for clearing HSV-1. In this review, we examine the findings on T cell immune responses during HSV-1 infection, which hold promise in the design of new vaccine candidates for HSV-1.
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8
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Abstract
In humans and mouse models, Foxp3(+) regulatory T cells are known to control all aspects of immune responses. However, only limited information exists on these cells' role in diseases of other animals. In this review, we cover the most important features and different types of regulatory T cells, which include those that are thymus-derived and peripherally induced, the mechanisms by which they control immune responses by targeting effector T cells and antigen-presenting cells, and most important, their role in animal health and diseases including cancer, infections, and other conditions such as hypersensitivities and autoimmunity. Although the literature regarding regulatory T cells in domestic animal species is still limited, multiple articles have recently emerged and are discussed. Moreover, we also discuss the evidence suggesting that regulatory T cells might limit the magnitude of effector responses, which can have either a positive or negative result, depending on the context of animal and human disease. In addition, the issue of plasticity is discussed because plasticity in regulatory T cells can result in the loss of their protective function in some microenvironments during disease. Lastly, the manipulation of regulatory T cells is discussed in assessing the possibility of their use as a treatment in the future.
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9
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Cárdenas D, Vélez G, Orfao A, Herrera MV, Solano J, Olaya M, Uribe AM, Saavedra C, Duarte M, Rodríguez M, López M, Fiorentino S, Quijano S. Epstein-Barr virus-specific CD8(+) T lymphocytes from diffuse large B cell lymphoma patients are functionally impaired. Clin Exp Immunol 2015; 182:173-83. [PMID: 26174440 PMCID: PMC4608507 DOI: 10.1111/cei.12682] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2015] [Indexed: 12/13/2022] Open
Abstract
Epstein-Barr virus (EBV) is a persistent virus with oncogenic capacity that has been implicated in the development of aggressive B cell lymphomas, primarily in immunosuppressed individuals, although it can be present in immunocompetent individuals. Changes in the function and clonal diversity of T lymphocytes might be implied by viral persistence and lymphoma development. The aim of the present study was to evaluate the frequency, phenotype, function and clonotypical distribution of EBV-specific T cells after peripheral blood stimulation with a virus lysate in newly diagnosed patients with diffuse large B cell lymphoma (DLBCL) aged more than 50 years without prior histories of clinical immunosuppression compared with healthy controls. Our results showed impaired EBV-specific immune responses among DLBCL patients that were associated primarily with decreased numbers of central and effector memory CD8(+) T lymphocytes. In contrast to healthy controls, only a minority of the patients showed CD4(+)/tumour necrosis factor (TNF)-α(+) T cells expressing T cell receptor (TCR)-Vβ17 and CD8(+)/TNF-α(+) T cells with TCR-Vβ5·2, Vβ9 and Vβ18 in response to EBV. Notably, the production of TNF-α was undetectable among TCR-Vβ5·3(+), Vβ11(+), Vβ12(+), Vβ16(+) and Vβ23(+) CD8(+) T cells. In addition, we observed decreased numbers of CD4(+)/TNF-α(+) and CD8(+)/TNF-α(+), CD8(+)/interleukin (IL)-2(+) and CD8(+)/TNF-α(+)/IL-2(+) T lymphocytes in the absence of T cells capable of producing TNF-α, IL-2 and IFN-γ after EBV stimulation simultaneously. Moreover, DLBCL patients displayed higher IL-10 levels both under baseline conditions and after EBV stimulation. These findings were also observed in patients with positive EBV viral loads. Prospective studies including a large number of patients are needed to confirm these findings.
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MESH Headings
- Aged
- Aged, 80 and over
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/virology
- Epstein-Barr Virus Infections/blood
- Epstein-Barr Virus Infections/immunology
- Epstein-Barr Virus Infections/virology
- Female
- Flow Cytometry
- Herpesvirus 4, Human/immunology
- Herpesvirus 4, Human/physiology
- Host-Pathogen Interactions/immunology
- Humans
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Interleukin-10/immunology
- Interleukin-10/metabolism
- Interleukin-2/immunology
- Interleukin-2/metabolism
- Lymphocyte Count
- Lymphoma, Large B-Cell, Diffuse/blood
- Lymphoma, Large B-Cell, Diffuse/immunology
- Lymphoma, Large B-Cell, Diffuse/virology
- Male
- Middle Aged
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Tumor Necrosis Factor-alpha/immunology
- Tumor Necrosis Factor-alpha/metabolism
- Viral Load/immunology
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Affiliation(s)
- D Cárdenas
- Grupo De Inmunobiología Y Biología Celular Departamento De Microbiología Facultad De Ciencias Pontificia Universidad JaverianaBogotá, Colombia
| | - G Vélez
- Grupo De Inmunobiología Y Biología Celular Departamento De Microbiología Facultad De Ciencias Pontificia Universidad JaverianaBogotá, Colombia
| | - A Orfao
- Servicio General De Citometría Y Departamento De Medicina, Centro De Investigación Del Cáncer (Instituto De Biología Molecular Y Celular Del Cáncer and IBSAL; CSIC-USAL), Universidad De SalamancaSalamanca, España
| | - M V Herrera
- Servicio De Hematología Hospital Universitario San Ignacio-Centro De Oncología Javeriano
| | - J Solano
- Servicio De Hematología Hospital Universitario San Ignacio-Centro De Oncología Javeriano
| | - M Olaya
- Departamento de Patología, Pontificia Universidad Javeriana, Hospital Universitario San Ignacio
| | - A M Uribe
- Departamento de Patología, Pontificia Universidad Javeriana, Hospital Universitario San Ignacio
| | - C Saavedra
- Grupo De Patología Fundación Santa Fe De Bogotá
| | - M Duarte
- Servicio De Hematología Fundación Santa Fe De BogotáBogotá, Colombia
| | - M Rodríguez
- Servicio De Hematología Fundación Santa Fe De BogotáBogotá, Colombia
| | - M López
- Fundación Cardiovascular De ColombiaFloridablanca, Colombia
| | - S Fiorentino
- Grupo De Inmunobiología Y Biología Celular Departamento De Microbiología Facultad De Ciencias Pontificia Universidad JaverianaBogotá, Colombia
| | - S Quijano
- Grupo De Inmunobiología Y Biología Celular Departamento De Microbiología Facultad De Ciencias Pontificia Universidad JaverianaBogotá, Colombia
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Liu S, Luo J, Liu Y, Tang S, Chen C, Cai H, Yu M, Zhang Y. CD4+Foxp3+regulatory T-cell number increases in the gastric tissue of C57BL/6 mice infected withHelicobacter pylori. APMIS 2015; 123:571-9. [DOI: 10.1111/apm.12388] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 02/20/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Sheng Liu
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
| | - Jingjing Luo
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
| | - Yapu Liu
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
| | - Shuangyang Tang
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
| | - Chaoqun Chen
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
| | - Hengling Cai
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
| | - Minjun Yu
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
| | - Yan Zhang
- Institute of Pathogenic Biology; University of South China; Hengyang Hunan China
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Doulberis M, Angelopoulou K, Kaldrymidou E, Tsingotjidou A, Abas Z, Erdman SE, Poutahidis T. Cholera-toxin suppresses carcinogenesis in a mouse model of inflammation-driven sporadic colon cancer. Carcinogenesis 2014; 36:280-90. [PMID: 25550315 DOI: 10.1093/carcin/bgu325] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Human studies and clues from animal models have provided important links between gastrointestinal (GI) tract bacteria and colon cancer. Gut microbiota antigenic stimuli play an important role in shaping the intestinal immune responses. Therefore, especially in the case of inflammation-associated colon cancer, gut bacteria antigens may affect tumorigenesis. The present study aimed to investigate the effects of the oral administration of a bacterial product with known immunomodulatory properties on inflammation-driven colorectal neoplasmatogenesis. For that, we used cholera-toxin and a well-established mouse model of colon cancer in which neoplasia is initiated by a single dose of the genotoxic agent azoxymethane (AOM) and subsequently promoted by inflammation caused by the colitogenic substance dextran sodium sulfate (DSS). We found that a single, low, non-pathogenic dose of CT, given orally at the beginning of each DSS treatment cycle downregulated neutrophils and upregulated regulatory T-cells and IL-10 in the colonic mucosa. The CT-induced disruption of the tumor-promoting character of DSS-induced inflammation led to the reduction of the AOM-initiated colonic polypoidogenesis. This result adds value to the emerging notion that certain GI tract bacteria or their products affect the immune system and render the microenvironment of preneoplastic lesions less favorable for promoting their evolution to cancer.
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Affiliation(s)
- Michael Doulberis
- Laboratory of Pathology, Laboratory of Biochemistry and Toxicology and Laboratory of Anatomy, Histology and Embryology, Faculty of Health Sciences, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece, Department of Agricultural Development, Democritus University of Thrace, Orestiada 68200, Greece and Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Eleni Kaldrymidou
- Laboratory of Pathology, Laboratory of Biochemistry and Toxicology and Laboratory of Anatomy, Histology and Embryology, Faculty of Health Sciences, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece, Department of Agricultural Development, Democritus University of Thrace, Orestiada 68200, Greece and Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Anastasia Tsingotjidou
- Laboratory of Anatomy, Histology and Embryology, Faculty of Health Sciences, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Zaphiris Abas
- Department of Agricultural Development, Democritus University of Thrace, Orestiada 68200, Greece and
| | - Suzan E Erdman
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Theofilos Poutahidis
- Laboratory of Pathology, Laboratory of Biochemistry and Toxicology and Laboratory of Anatomy, Histology and Embryology, Faculty of Health Sciences, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece, Department of Agricultural Development, Democritus University of Thrace, Orestiada 68200, Greece and Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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12
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Chevalier MF, Didier C, Petitjean G, Karmochkine M, Girard PM, Barré-Sinoussi F, Scott-Algara D, Weiss L. Phenotype alterations in regulatory T-cell subsets in primary HIV infection and identification of Tr1-like cells as the main interleukin 10-producing CD4+ T cells. J Infect Dis 2014; 211:769-79. [PMID: 25281758 DOI: 10.1093/infdis/jiu549] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Conventional regulatory T cells (Tregs) can suppress human immunodeficiency virus type 1 (HIV-1)-specific immune responses but cannot control immune activation in primary HIV infection. Here, we characterized Treg subsets, using recently defined phenotypic delineation, and analyzed the relative contribution of cell subsets to the production of immunosuppressive cytokines in primary HIV infection. METHODS In a longitudinal prospective study, ex vivo phenotyping of fresh peripheral blood mononuclear cells from patients with primary HIV infection was performed at baseline and month 6 of follow-up to characterize Treg subsets, immune activation, and cytokine production in isolated CD4(+) T cells. RESULTS The frequency of CD4(+)CD25(+)CD127(low) Tregs and the distribution between the naive, memory, and activated/memory Treg subsets was similar in patients and healthy donors. However, Tregs from patients with primary HIV infection showed peculiar phenotypic profiles, such as elevated FoxP3, ICOS, and CTLA-4 expression, with CTLA-4 expression strikingly increased in all Treg subsets both at baseline and month 6 of follow-up. The great majority of interleukin 10 (IL-10)-producing CD4(+) T cells were FoxP3(neg) (ie, Tr1-like cells). In contrast to conventional Tregs, Tr1-like cells were inversely correlated with immune activation and not associated with lower effector T-cell responses. CONCLUSION FoxP3(neg) Tr1-like cells-major contributors to IL-10 production-may have a beneficial role by controlling immune activation in early HIV infection.
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Affiliation(s)
- Mathieu F Chevalier
- Régulation des infections rétrovirales, Institut Pasteur Université Paris Diderot
| | - Céline Didier
- Régulation des infections rétrovirales, Institut Pasteur
| | - Gaël Petitjean
- Régulation des infections rétrovirales, Institut Pasteur
| | | | | | | | | | - Laurence Weiss
- Régulation des infections rétrovirales, Institut Pasteur Université Paris Descartes, Sorbonne Paris Cité Hôpital Européen Georges Pompidou
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13
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Johnstone J, Parsons R, Botelho F, Millar J, McNeil S, Fulop T, McElhaney J, Andrew MK, Walter SD, Devereaux PJ, Malekesmaeili M, Brinkman RR, Mahony J, Bramson J, Loeb M. Immune biomarkers predictive of respiratory viral infection in elderly nursing home residents. PLoS One 2014; 9:e108481. [PMID: 25275464 PMCID: PMC4183538 DOI: 10.1371/journal.pone.0108481] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/12/2014] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE To determine if immune phenotypes associated with immunosenescence predict risk of respiratory viral infection in elderly nursing home residents. METHODS Residents ≥ 65 years from 32 nursing homes in 4 Canadian cities were enrolled in Fall 2009, 2010 and 2011, and followed for one influenza season. Following influenza vaccination, peripheral blood mononuclear cells (PBMCs) were obtained and analysed by flow cytometry for T-regs, CD4+ and CD8+ T-cell subsets (CCR7+CD45RA+, CCR7-CD45RA+ and CD28-CD57+) and CMV-reactive CD4+ and CD8+ T-cells. Nasopharyngeal swabs were obtained and tested for viruses in symptomatic residents. A Cox proportional hazards model adjusted for age, sex and frailty, determined the relationship between immune phenotypes and time to viral infection. RESULTS 1072 residents were enrolled; median age 86 years and 72% female. 269 swabs were obtained, 87 were positive for virus: influenza (24%), RSV (14%), coronavirus (32%), rhinovirus (17%), human metapneumovirus (9%) and parainfluenza (5%). In multivariable analysis, high T-reg% (HR 0.41, 95% CI 0.20-0.81) and high CMV-reactive CD4+ T-cell% (HR 1.69, 95% CI 1.03-2.78) were predictive of respiratory viral infection. CONCLUSIONS In elderly nursing home residents, high CMV-reactive CD4+ T-cells were associated with an increased risk and high T-regs were associated with a reduced risk of respiratory viral infection.
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Affiliation(s)
- Jennie Johnstone
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
| | - Robin Parsons
- McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada
| | - Fernando Botelho
- McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada
| | - Jamie Millar
- McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada
| | - Shelly McNeil
- Canadian Center for Vaccinology, IWK Health Centre and Capital Health, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Tamas Fulop
- Department of Medicine, Geriatrics Division, Research Center on Aging, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Janet McElhaney
- Department of Medicine, Northern Ontario School of Medicine, Sudbury, Ontario, Canada
| | - Melissa K. Andrew
- Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Stephen D. Walter
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
| | - P. J. Devereaux
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | - Ryan R. Brinkman
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - James Mahony
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Jonathan Bramson
- McMaster Immunology Research Centre, McMaster University, Hamilton, Ontario, Canada
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Mark Loeb
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
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14
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Veiga-Parga T, Sehrawat S, Rouse BT. Role of regulatory T cells during virus infection. Immunol Rev 2014; 255:182-96. [PMID: 23947355 DOI: 10.1111/imr.12085] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The host response to viruses includes multiple cell types that have regulatory function. Most information focuses on CD4(+) regulatory T cells that express the transcription factor Foxp3(+) (Tregs), which are the topic of this review. We explain how viruses through specific and non-specific means can trigger the response of thymus-derived natural Tregs as well as induce Tregs. The latter derive under appropriate stimulation conditions either from uncommitted precursors or from differentiated cells that convert to become Tregs. We describe instances where Tregs appear to limit the efficacy of antiviral protective immunity and other, perhaps more common, immune-mediated inflammatory conditions, where the Tregs function to limit the extent of tissue damage that occurs during a virus infection. We discuss the controversial roles that Tregs may play in the pathogenesis of human immunodeficiency and hepatitis C virus infections. The issue of plasticity is discussed, as this may result in Tregs losing their protective function when present in inflammatory environments. Finally, we mention approaches used to manipulate Treg numbers and function and assess their current value and likely future success to manage the outcome of virus infection, especially those that are responsible for chronic tissue damage.
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Affiliation(s)
- Tamara Veiga-Parga
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
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15
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Okubo Y, Mera T, Wang L, Faustman DL. Homogeneous expansion of human T-regulatory cells via tumor necrosis factor receptor 2. Sci Rep 2013; 3:3153. [PMID: 24193319 PMCID: PMC3818650 DOI: 10.1038/srep03153] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 10/17/2013] [Indexed: 02/07/2023] Open
Abstract
T-regulatory cells (T(regs)) are a rare lymphocyte subtype that shows promise for treating infectious disease, allergy, graft-versus-host disease, autoimmunity, and asthma. Clinical applications of T(regs) have not been fully realized because standard methods of expansion ex vivo produce heterogeneous progeny consisting of mixed populations of CD4 + T cells. Heterogeneous progeny are risky for human clinical trials and face significant regulatory hurdles. With the goal of producing homogeneous T(regs), we developed a novel expansion protocol targeting tumor necrosis factor receptors (TNFR) on T(regs). In in vitro studies, a TNFR2 agonist was found superior to standard methods in proliferating human T(regs) into a phenotypically homogeneous population consisting of 14 cell surface markers. The TNFR2 agonist-expanded T(regs) also were functionally superior in suppressing a key T(reg) target cell, cytotoxic T-lymphocytes. Targeting the TNFR2 receptor during ex vivo expansion is a new means for producing homogeneous and potent human T(regs) for clinical opportunities.
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Affiliation(s)
- Yoshiaki Okubo
- Immunobiology Laboratory, Massachusetts General Hospital and Harvard Medical School, Rm 3602, MGH-East, Bldg 149, 13th Street, Boston, MA 02129
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16
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Fernandez MA, Yu U, Zhang G, White R, Sparwasser T, Alexander SI, Jones CA. Treg depletion attenuates the severity of skin disease from ganglionic spread after HSV-2 flank infection. Virology 2013; 447:9-20. [PMID: 24210095 DOI: 10.1016/j.virol.2013.08.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/03/2013] [Accepted: 08/22/2013] [Indexed: 10/26/2022]
Abstract
Regulatory T cells (Tregs) attenuate lesion severity and disease after HSV ocular or genital infection, but their role in cutaneous infection remains unclear. Treg depletion (anti-CD25 mAb in C57BL/6 mice or diphtheria toxin (DT) in DEREG mice) prior to tk-deficient HSV-2 flank infection significantly decreased skin lesion severity, granulocyte receptor-1(Gr-1(+)) cell number, and chemokine (KC) expression in the secondary skin, but significantly increased immune effectors and chemokine expression (MCP-1, KC, VEGF-A) in the draining LN, and activated, interferon-γ producing CD8(+)T cells in the ganglia. Treg depletion also significantly reduced HSV-2 DNA in the ganglia. Thus, Tregs increase the severity of recurrent skin lesions, and differentially alter chemokine expression and immune effector homing in the skin and LN after cutaneous infection, and limit CD8(+) T cell responses in the ganglia. Our data suggests that effects of Treg manipulation on recurrent herpes lesions should be considered when developing Treg mediated therapeutics.
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Affiliation(s)
- Marian A Fernandez
- Centres for Perinatal Infection Research and Kidney Research, The Children's Hospital at Westmead, Westmead, NSW, Australia; Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Locked Bag 4001, Westmead, NSW 2145, Australia.
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17
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Milner JJ, Sheridan PA, Karlsson EA, Schultz-Cherry S, Shi Q, Beck MA. Diet-induced obese mice exhibit altered heterologous immunity during a secondary 2009 pandemic H1N1 infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 191:2474-85. [PMID: 23904168 PMCID: PMC3756476 DOI: 10.4049/jimmunol.1202429] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
During the 2009 pandemic H1N1 influenza A virus (pH1N1) outbreak, obese individuals were at greater risk for morbidity and mortality from pandemic infection. However, the mechanisms contributing to greater infection severity in obese individuals remain unclear. Although most individuals lacked pre-existing, neutralizing Ab protection to the novel pH1N1 virus, heterologous defenses conferred from exposure to circulating strains or vaccination have been shown to impart protection against pH1N1 infection in humans and mice. Because obese humans and mice have impaired memory T cell and Ab responses following influenza vaccination or infection, we investigated the impact of obesity on heterologous protection from pH1N1 infection using a mouse model of diet-induced obesity. Lean and obese mice were infected with influenza A/Puerto Rico/8/34 (PR8) and 5 wk later challenged with a lethal dose of heterologous pH1N1. Cross-neutralizing Ab protection was absent in this model, but obese mice exhibited a significantly lower level of nonneutralizing, cross-reactive pH1N1 nucleoprotein Abs following the primary PR8 infection. Further, obese mice had elevated viral titers, greater lung inflammation and lung damage, and more cytotoxic memory CD8(+) T cells in the lung airways. Although obese mice had more regulatory T cells (Tregs) in the lung airways than did lean controls during the pH1N1 challenge, Tregs isolated from obese mice were 40% less suppressive than Tregs isolated from lean mice. In sum, excessive inflammatory responses to pH1N1 infection, potentially owing to greater viral burden and impaired Treg function, may be a novel mechanism by which obesity contributes to greater pH1N1 severity.
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Affiliation(s)
- J. Justin Milner
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Patricia A. Sheridan
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Erik A. Karlsson
- Department of Infectious Diseases, St. Jude Children’s Research Hospital Memphis, Memphis, TN, USA
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children’s Research Hospital Memphis, Memphis, TN, USA
| | - Qing Shi
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Melinda A. Beck
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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18
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Suryawanshi A, Cao Z, Thitiprasert T, Zaidi TS, Panjwani N. Galectin-1-mediated suppression of Pseudomonas aeruginosa-induced corneal immunopathology. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:6397-409. [PMID: 23686486 PMCID: PMC3689592 DOI: 10.4049/jimmunol.1203501] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Corneal infection with Pseudomonas aeruginosa leads to a severe immunoinflammatory lesion, often causing vision impairment and blindness. Although past studies have indicated a critical role for CD4(+) T cells, particularly Th1 cells, in corneal immunopathology, the relative contribution of recently discovered Th17 and regulatory T cells is undefined. In this study, we demonstrate that after corneal P. aeruginosa infection, both Th1 and Th17 cells infiltrate the cornea with increased representation of Th17 cells. In addition to Th1 and Th17 cells, regulatory T cells also migrate into the cornea during early as well as late stages of corneal pathology. Moreover, using galectin-1 (Gal-1), an immunomodulatory carbohydrate-binding molecule, we investigated whether shifting the balance among various CD4(+) T cell subsets can modulate P. aeruginosa-induced corneal immunopathology. We demonstrate in this study that local recombinant Gal-1 (rGal-1) treatment by subconjunctival injections significantly diminishes P. aeruginosa-mediated corneal inflammation through multiple mechanisms. Specifically, in our study, rGal-1 treatment significantly diminished corneal infiltration of total CD45(+) T cells, neutrophils, and CD4(+) T cells. Furthermore, rGal-1 treatment significantly reduced proinflammatory Th17 cell response in the cornea as well as local draining lymph nodes. Also, rGal-1 therapy promoted anti-inflammatory Th2 and IL-10 response in secondary lymphoid organs. Collectively, our results indicate that corneal P. aeruginosa infection induces a strong Th17-mediated corneal pathology, and treatment with endogenously derived protein such as Gal-1 may be of therapeutic value for the management of bacterial keratitis, a prevalent cause of vision loss and blindness in humans worldwide.
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Affiliation(s)
- Amol Suryawanshi
- New England Eye Center and Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111
| | - Zhiyi Cao
- New England Eye Center and Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111
| | - Thananya Thitiprasert
- New England Eye Center and Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111
| | - Tanveer S. Zaidi
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115
| | - Noorjahan Panjwani
- New England Eye Center and Department of Ophthalmology, Tufts University School of Medicine, Boston, MA 02111
- Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111
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19
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McCarthy Ú, Casadei E, Wang T, Secombes CJ. Red mark syndrome in rainbow trout Oncorhynchus mykiss: investigation of immune responses in lesions using histology, immunohistochemistry and analysis of immune gene expression. FISH & SHELLFISH IMMUNOLOGY 2013; 34:1119-1130. [PMID: 23403161 DOI: 10.1016/j.fsi.2013.01.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 11/20/2012] [Accepted: 01/22/2013] [Indexed: 06/01/2023]
Abstract
Red mark syndrome (RMS) is an economically significant disease which affects farmed rainbow trout in the United Kingdom, in the US and in mainland Europe. From the pattern of incidence, it appears to be transmissable, although no causative agent has yet been identified. RMS presents as a severe lymphocytic infiltration centred on the dermis and an alternative, host-focused approach was taken to understand the disease through investigating immune responses occurring in the lesion. Lesion and non-lesion skin at different stages of lesion development were examined using histochemistry and immunohistochemistry on paraffin sections. Expression of immune-related genes was compared between lesion and non-lesion skin. Investigation of early stage lesions suggested that the initial immune response is targeted at the region of the scale pocket, with lymphocyte infiltration and anti-tumour necrosis factor (TNF)-α staining of the stratum spongiosum, and increased numbers of major histocompatibility complex (MHC) II-positive cells immediately adjacent to the scale pocket. Gene expression analysis suggested a counterbalancing T helper (Th)1 and T regulatory (Treg) - type response is occurring in the lesion, with repression of Th2 and Th17-type responses.
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Affiliation(s)
- Ú McCarthy
- Ellis Building, Marine Scotland Science, Marine Laboratory, 375 Victoria Road, PO Box 101, Aberdeen AB11 9DB, Scotland, UK.
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20
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Veiga-Parga T, Suryawanshi A, Mulik S, Giménez F, Sharma S, Sparwasser T, Rouse BT. On the role of regulatory T cells during viral-induced inflammatory lesions. THE JOURNAL OF IMMUNOLOGY 2012; 189:5924-33. [PMID: 23129753 DOI: 10.4049/jimmunol.1202322] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ocular HSV-1 infection can result in stromal keratitis, a blinding immunoinflammatory lesion that represents an immunopathological response to the infection. CD4(+) T cells are the main orchestrators, and lesions are more severe if the regulatory T cell (Treg) response is compromised from the onset of infection. Little is known about the role of Foxp3(+)CD4(+) Tregs during ongoing inflammatory reactions, which is the topic of this article. We used DEREG mice and depleted Tregs at different times postinfection. We show that lesions became more severe even when depletion was begun in the clinical phase of the disease. This outcome was explained both by Tregs' influence on the activity of inflammatory effector T cells at the lesion site and by an effect in lymphoid tissues that led to reduced numbers of effectors and less trafficking of T cells and neutrophils to the eye. Our results demonstrate that Tregs can beneficially influence the impact of ongoing tissue-damaging responses to a viral infection and imply that therapies boosting Treg function in the clinical phase hold promise for controlling a lesion that is an important cause of human blindness.
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Affiliation(s)
- Tamara Veiga-Parga
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
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21
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Abstract
Natural regulatory T cells (Tregs) participate in responses to various chronic infections including HIV. HIV infection is associated with a progressive CD4 lymphopenia and defective HIV-specific CD8 responses known to play a key role in the control of viral replication. Persistent immune activation is a hallmark of HIV infection and is involved in disease progression independent of viral load. The consequences of Treg expansion, observed in HIV infection, could be either beneficial, by suppressing generalized T-cell activation, or detrimental, by weakening HIV-specific responses and thus contributing to viral persistence. The resulting balance between Tregs contrasting outcomes might have critical implications in pathogenesis. Topics covered in this review include HIV-induced alterations of Tregs, Treg cell dynamics in blood and tissues, Treg-suppressive function, and the relationship between Tregs and immune activation. This review also provides a focus on the role of CD39(+) Tregs and other regulatory cell subsets. All these issues will be explored in different situations including acute and chronic infection, antiretroviral treatment-mediated viral control, and spontaneous viral control. Results must be interpreted with regard to both the Treg definition used in context and to the setting of the disease in an attempt to draw clearer conclusions from the apparently conflicting results.
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