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Mundra A, Yegiazaryan A, Karsian H, Alsaigh D, Bonavida V, Frame M, May N, Gargaloyan A, Abnousian A, Venketaraman V. Pathogenicity of Type I Interferons in Mycobacterium tuberculosis. Int J Mol Sci 2023; 24:3919. [PMID: 36835324 PMCID: PMC9965986 DOI: 10.3390/ijms24043919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/08/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Tuberculosis (TB) is a leading cause of mortality due to infectious disease and rates have increased during the emergence of COVID-19, but many of the factors determining disease severity and progression remain unclear. Type I Interferons (IFNs) have diverse effector functions that regulate innate and adaptive immunity during infection with microorganisms. There is well-documented literature on type I IFNs providing host defense against viruses; however, in this review, we explore the growing body of work that indicates high levels of type I IFNs can have detrimental effects to a host fighting TB infection. We report findings that increased type I IFNs can affect alveolar macrophage and myeloid function, promote pathological neutrophil extracellular trap responses, inhibit production of protective prostaglandin 2, and promote cytosolic cyclic GMP synthase inflammation pathways, and discuss many other relevant findings.
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Affiliation(s)
- Akaash Mundra
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Aram Yegiazaryan
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Haig Karsian
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Dijla Alsaigh
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Victor Bonavida
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Mitchell Frame
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Nicole May
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Areg Gargaloyan
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Arbi Abnousian
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Vishwanath Venketaraman
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91768, USA
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2
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Panda S, Seelan DM, Faisal S, Arora A, Luthra K, Palanichamy JK, Mohan A, Vikram NK, Gupta NK, Ramakrishnan L, Singh A. Chronic hyperglycemia drives alterations in macrophage effector function in pulmonary tuberculosis. Eur J Immunol 2022; 52:1595-1609. [PMID: 36066992 DOI: 10.1002/eji.202249839] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/05/2022] [Accepted: 09/05/2022] [Indexed: 12/14/2022]
Abstract
Diabetes mellitus (DM) alters immune responses and given the rising prevalence of DM in tuberculosis (TB) endemic countries; hyperglycemia can be a potential risk factor for active TB development. However, the impact of hyperglycemia on TB-specific innate immune response in terms of macrophage functions remains poorly addressed. We assessed macrophage effector functions in uncontrolled DM patients with or without TB infection (PTB+DM and DM), non-diabetic TB patients (PTB), and non-diabetic-uninfected controls. Phagocytic capacity against BCG and surface expression of different pattern recognition receptors (PRRs) (CD11b, CD14, CD206, MARCO, and TLR-2) were measured via flow cytometry. Effector molecules (ROS and NO) required for bacterial killing were assessed via DCFDA and Griess reaction respectively. A systematic dysregulation in phagocytic capacity with concurrent alterations in the expression pattern of key PRRs (CD11b, MARCO, and CD206) was observed in PTB+DM. These altered PRR expressions were associated with decreased phagocytic capacity of macrophages. Similarly, ROS was aberrantly higher while NO was lower in PTB+DM. These altered macrophage functions were positively correlated with increasing disease severity. Our results highlight several key patterns of immune dysregulation against TB infection under hyperglycemic conditions and highlight a negative impact of hyperglycemia with etiology and progression of TB.
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Affiliation(s)
- Sudhasini Panda
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Diravya M Seelan
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Shah Faisal
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Alisha Arora
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Kalpana Luthra
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India
| | | | - Anant Mohan
- Department of Pulmonary Medicine, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Naval K Vikram
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Neeraj Kumar Gupta
- Department of Pulmonary Medicine, VMMC and Safdarjung Hospital, New Delhi, 110029, India
| | - Lakshmy Ramakrishnan
- Department of Cardiac Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Archana Singh
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029, India
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3
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Singh S, Saavedra-Avila NA, Tiwari S, Porcelli SA. A century of BCG vaccination: Immune mechanisms, animal models, non-traditional routes and implications for COVID-19. Front Immunol 2022; 13:959656. [PMID: 36091032 PMCID: PMC9459386 DOI: 10.3389/fimmu.2022.959656] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/01/2022] [Indexed: 11/21/2022] Open
Abstract
Bacillus Calmette-Guerin (BCG) has been used as a vaccine against tuberculosis since 1921 and remains the only currently approved vaccine for this infection. The recent discovery that BCG protects against initial infection, and not just against progression from latent to active disease, has significant implications for ongoing research into the immune mechanisms that are relevant to generate a solid host defense against Mycobacterium tuberculosis (Mtb). In this review, we first explore the different components of immunity that are augmented after BCG vaccination. Next, we summarize current efforts to improve the efficacy of BCG through the development of recombinant strains, heterologous prime-boost approaches and the deployment of non-traditional routes. These efforts have included the development of new recombinant BCG strains, and various strategies for expression of important antigens such as those deleted during the M. bovis attenuation process or antigens that are present only in Mtb. BCG is typically administered via the intradermal route, raising questions about whether this could account for its apparent failure to generate long-lasting immunological memory in the lungs and the inconsistent level of protection against pulmonary tuberculosis in adults. Recent years have seen a resurgence of interest in the mucosal and intravenous delivery routes as they have been shown to induce a better immune response both in the systemic and mucosal compartments. Finally, we discuss the potential benefits of the ability of BCG to confer trained immunity in a non-specific manner by broadly stimulating a host immunity resulting in a generalized survival benefit in neonates and the elderly, while potentially offering benefits for the control of new and emerging infectious diseases such as COVID-19. Given that BCG will likely continue to be widely used well into the future, it remains of critical importance to better understand the immune responses driven by it and how to leverage these for the design of improved vaccination strategies against tuberculosis.
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Affiliation(s)
- Shivani Singh
- Department of Medicine, New York University School of Medicine, New York, NY, United States
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, United States
- Department of Medicine, Albert Einstein College of Medicine, New York, NY, United States
- *Correspondence: Shivani Singh,
| | | | - Sangeeta Tiwari
- Department of Biological Sciences and Border Biomedical Research Center, University of Texas at El Paso, Texas, United States
| | - Steven A. Porcelli
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, United States
- Department of Medicine, Albert Einstein College of Medicine, New York, NY, United States
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4
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Singh S, Bolz M, Cornelius A, Desvignes L. Intravenous BCG driven antigen recognition in a murine tuberculosis model. Comp Immunol Microbiol Infect Dis 2022; 87:101838. [PMID: 35700556 DOI: 10.1016/j.cimid.2022.101838] [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: 02/28/2022] [Revised: 06/02/2022] [Accepted: 06/04/2022] [Indexed: 10/18/2022]
Abstract
Bacille Calmette-Guerin (BCG) is the only approved vaccine against tuberculosis but the subcutaneous route does not provide for the elimination of Mycobacterium tuberculosis (Mtb), thus highlighting the need for investigating other routes of administration. We used a unique set of 60 peptide pools with unprecedented coverage of the bacterium that had previously been used to study T cell responses in subjects latently infected with Mtb. We showed that intravenous BCG vaccination of C57BL/6 mice elicited a more robust IFN-γ response from splenocytes than the subcutaneous route, with the highest responses driven by the Ag85A/B and PE/PPE family epitopes, followed by TB10.4 and Esx-1. We then compared the spectrum of antigen recognition in BCG-naïve H37Rv-challenged and BCG-vaccinated H37Rv-challenged mice. Peptides belonging to TB10.4, ESAT-6, CFP-10, Ag85A/Ag85B, PE/PPE and Esx families up-regulated IFN-γ production in the lungs of BCG-naïve H37Rv-challenged mice but the response was much lower in the BCG-vaccinated group. Historically, a limited number of Mtb antigens have been used to study T cell responses in TB. The goal of using this 60-peptide assay was to define T cell responses in TB down to the epitope level. We envision that the use of broad antigen panels such as ours in conjunction with studies of bacterial load reduction will help delineate the protective efficacy of 'groups' of antigens.
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Affiliation(s)
- Shivani Singh
- Division of Pulmonary and Critical Care Medicine, USA.
| | - Miriam Bolz
- Division of Infectious Diseases and Immunology, Department of Medicine, USA
| | - Amber Cornelius
- Division of Infectious Diseases and Immunology, Department of Medicine, USA
| | - Ludovic Desvignes
- Division of Infectious Diseases and Immunology, Department of Medicine, USA; Office of Science & Research, New York University Grossman School of Medicine, New York, USA
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5
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Discovery of nitric oxide-inducing activities of synthetic LAM glycan motifs prepared by scalable rapid syntheses. Carbohydr Polym 2022; 296:119637. [DOI: 10.1016/j.carbpol.2022.119637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/01/2022] [Accepted: 05/16/2022] [Indexed: 11/17/2022]
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6
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Zhu T, Liu H, Su L, Xiong X, Wang J, Xiao Y, Zhu Y, Peng Y, Dawood A, Hu C, Chen X, Chen H, Chen Y, Guo A. MicroRNA-18b-5p Downregulation Favors Mycobacterium tuberculosis Clearance in Macrophages via HIF-1α by Promoting an Inflammatory Response. ACS Infect Dis 2021; 7:800-810. [PMID: 33705114 DOI: 10.1021/acsinfecdis.0c00650] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The modulation of the interaction between macrophages and Mycobacterium tuberculosis (M.tb) through microRNA during M.tb infection is increasingly capturing the attention of researchers. However, the potential role of microRNA-18b-5p (miR-18b) is not elucidated yet. In this study, miR-18b was found to be downregulated in M.tb-infected macrophage cell lines (THP-1 and RAW264.7) in time- and dose-dependent manners. Furthermore, when the miR-18b mimic and inhibitor and small interfering RNA hypoxia-inducible factor 1α (si-HIF-1α) were transfected into the macrophages separately or in combination, it was found that miR-18b targeted hypoxia-inducible factor 1α (HIF-1α). During M.tb infection, the decrease in the expression of miR-18b facilitated HIF-1α expression, which led to the increased production of pro-inflammatory cytokines, such as IL-6, resulting in decreased bacterial survival in the host cells. Moreover, the phosphorylation of p38 MAPK and NF-κB p65 was activated by the miR-18b inhibitor. Our findings expand the current understanding of the M.tb-cell interaction mechanism and provide a potential target to control M.tb infection.
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Affiliation(s)
- Tingting Zhu
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Han Liu
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Li Su
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xuekai Xiong
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Jieru Wang
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yao Xiao
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yifan Zhu
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Development of Veterinary Diagnostic Products and of Agriculture and Rural Affairs, Huazhong Agriculture University, Wuhan, Hubei 430070, China
| | - Yongchong Peng
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Ali Dawood
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Department of Medicine and Infectious Diseases, Faculty of Veterinary Medicine, University of Sadat City, Sadat City 32511, Egypt
| | - Changmin Hu
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xi Chen
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Huanchun Chen
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yingyu Chen
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Development of Veterinary Diagnostic Products and of Agriculture and Rural Affairs, Huazhong Agriculture University, Wuhan, Hubei 430070, China
| | - Aizhen Guo
- The State Key Laboratory of Agricultural Microbiology, Wuhan, Hubei 430070, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
- Key Laboratory of Development of Veterinary Diagnostic Products and of Agriculture and Rural Affairs, Huazhong Agriculture University, Wuhan, Hubei 430070, China
- Key Laboratory of Ruminant Bio-products of Ministry of Agriculture and Rural Affairs, Huazhong Agriculture University, Wuhan, Hubei 430070, China
- Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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7
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Adams LB. Susceptibility and resistance in leprosy: Studies in the mouse model. Immunol Rev 2021; 301:157-174. [PMID: 33660297 PMCID: PMC8252540 DOI: 10.1111/imr.12960] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 12/24/2022]
Abstract
Leprosy is a chronic granulomatous infectious disease caused by the pathogen, Mycobacterium leprae, and the more recently discovered, M. lepromatosis. Described in 1873, M. leprae was among the first microorganisms to be proposed as a cause of a human infectious disease. As an obligate intracellular bacterium, it has still not thus far been reproducibly cultivated in axenic medium or cell cultures. Shepard's mouse footpad assay, therefore, was truly a breakthrough in leprosy research. The generation of immunosuppressed and genetically engineered mice, along with advances in molecular and cellular techniques, has since offered more tools for the study of the M. leprae–induced granuloma. While far from perfect, these new mouse models have provided insights into the immunoregulatory mechanisms responsible for the spectrum of this complex disease.
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Affiliation(s)
- Linda B Adams
- Department of Health and Human Services, Health Resources and Services Administration, Healthcare Systems Bureau, National Hansen's Disease Programs Laboratory Research Branch, Baton Rouge, LA, USA
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8
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Mansury D, Ghazvini K, Amel Jamehdar S, Badiee A, Tafaghodi M, Nikpoor AR, Amini Y, Jaafari MR. Enhancement of the effect of BCG vaccine against tuberculosis using DDA/TDB liposomes containing a fusion protein of HspX, PPE44, and EsxV. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2019; 47:370-377. [DOI: 10.1080/21691401.2018.1557674] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Davood Mansury
- Antimicrobial Resistance Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Kiarash Ghazvini
- Antimicrobial Resistance Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saeid Amel Jamehdar
- Antimicrobial Resistance Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Badiee
- Nanotechnology Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmaceutical Nanotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohsen Tafaghodi
- Nanotechnology Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmaceutical Nanotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amin Reza Nikpoor
- Department of Immunology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Yousef Amini
- Department of Microbiology and Virology, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Mahmoud Reza Jaafari
- Nanotechnology Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmaceutical Nanotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Biotechnology Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran
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9
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The Immunoregulation of Th17 in Host against Intracellular Bacterial Infection. Mediators Inflamm 2018; 2018:6587296. [PMID: 29743811 PMCID: PMC5884031 DOI: 10.1155/2018/6587296] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 02/04/2018] [Indexed: 12/14/2022] Open
Abstract
T helper 17 cells (Th17) constitute a distinct subset of helper T cells with a unique transcriptional profile (STAT3, RORγ, and RORα), cytokine production pattern (IL17 family), and requirement of specific cytokines for their differentiation (TGF-β, IL6, IL21, and IL23). Recent studies involving experimental animals and humans have shown that Th17/IL17 plays a crucial role in host defense against a variety of pathogens, including bacteria and viruses. The underlying mechanisms by which Th17 performs include dendritic cell (DC) regulation, neutrophil recruitment, Th1 modulation, and T regulatory cell (Treg) balance. In recent years, researchers have generated an accumulating wealth of evidence on the role of Th17/IL17 in protective immunity to intracellular bacterial pathogens, such as Mycobacterium tuberculosis and Chlamydia trachomatis, which are one of the most important pathogens that inflict significant socioeconomic burden across the globe. In this article, we reviewed the current literature on the functions and mechanisms by which Th17/IL17 responds to intracellular bacterial infections. A better understanding of Th17/IL17 immunity to pathogens would be crucial for developing effective prophylactics and therapeutics.
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10
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Jamaati H, Mortaz E, Pajouhi Z, Folkerts G, Movassaghi M, Moloudizargari M, Adcock IM, Garssen J. Nitric Oxide in the Pathogenesis and Treatment of Tuberculosis. Front Microbiol 2017; 8:2008. [PMID: 29085351 PMCID: PMC5649180 DOI: 10.3389/fmicb.2017.02008] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/29/2017] [Indexed: 12/21/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is globally known as one of the most important human pathogens. Mtb is estimated to infect nearly one third of the world's population with many subjects having a latent infection. Thus, from an estimated 2 billion people infected with Mtb, less than 10% may develop symptomatic TB. This indicates that the host immune system may constrain pathogen replication in most infected individuals. On entering the lungs of the host, Mtb initially encounters resident alveolar macrophages which can engulf and subsequently eliminate intracellular microbes via a plethora of bactericidal mechanisms including the generation of free radicals such as reactive oxygen and nitrogen species. Nitric oxide (NO), a key anti-mycobacterial molecule, is detected in the exhaled breath of patients infected with Mtb. Recent knowledge regarding the regulatory role of NO in airway function and Mtb proliferation paves the way of exploiting the beneficial effects of this molecule for the treatment of airway diseases. Here, we discuss the importance of NO in the pathogenesis of TB, the diagnostic use of exhaled and urinary NO in Mtb infection and the potential of NO-based treatments.
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Affiliation(s)
- Hamidreza Jamaati
- Chronic Respiratory Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Esmaeil Mortaz
- Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Zeinab Pajouhi
- Chronic Respiratory Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gert Folkerts
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Mehrnaz Movassaghi
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
| | - Milad Moloudizargari
- Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ian M Adcock
- Cell and Molecular Biology Group, Airways Disease Section, Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London, United Kingdom.,Priority Research Centre for Asthma and Respiratory Disease, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW, Australia
| | - Johan Garssen
- Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands.,Nutricia Research Centre for Specialized Nutrition, Utrecht, Netherlands
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11
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Liu W, Xu Y, Shen H, Yan J, Yang E, Wang H. Recombinant Bacille Calmette-Guérin coexpressing Ag85B-IFN-γ enhances the cell-mediated immunity in C57BL/6 mice. Exp Ther Med 2017; 13:2339-2347. [PMID: 28565847 PMCID: PMC5443280 DOI: 10.3892/etm.2017.4273] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 01/31/2017] [Indexed: 12/16/2022] Open
Abstract
The only available vaccine against pulmonary tuberculosis is Bacille Calmette-Guérin (BCG). As the efficacy reported of the vaccine is not up to the mark, there is an urgent need to develop improved anti-tuberculosis vaccines. Antigen 85B (Ag85B) is a very promising vaccine candidate molecule of Mycobacterium tuberculosis and interferon (IFN)-γ and has been considered the most attractive correlate of protective immunity. The aim of this study was to construct a novel recombinant BCG (rBCG) to secrete Ag85B and mouse IFN-γ under control of the Mycobacterial heat shock protein 60 (hsp60) promoter and the antigen signal sequence. Second aim of the present study is to evaluate the immune response in C57BL/6 elicted by the new rBCG. Expression of the fusion protein was readily detectable by western blotting and IFN-γ bioactivity was detected indirectly by enzyme-linked immunosorbent assay (ELISA). Compared with BCG, rBCG::Ag85B-IFN-γ was substantially more active in inducing the production of IFN-γ and tumor necrosis factor (TNF)-α from mouse splenocytes. ELISA analysis for IgG, IgG1 and IgG2c showed that rBCG::Ag85B-IFN-γ induced higher titer of Ag85B and facilitated Th1 type immune response. rBCG::Ag85B-IFN-γ also improved nitric oxide production levels and enhanced antigen-specific splenocyte proliferation. Moreover, rBCG::Ag85B-IFN-γ induced human monocytes such as THP-1 cells to enhance expression of CD80, CD86, CD40 and HLA-DR. Flow cytometry analysis confirmed that rBCG::Ag85B-IFN-γ significantly activated CD4+ T cells. Assessing combinations of IFN-γ, TNF-α and interleukin-2 at the single-cell level by multiparameter flow cytometry, we found that rBCG::Ag85B-IFN-γ improved the multifunctional T cells level in comparison to BCG. In conclusion, the present study indicates that rBCG::Ag85B-IFN-γ increases cell mediated immune response and is a potential candidate vaccine for immunotherapeutic protocols against pulmonary tuberculosis.
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Affiliation(s)
- Wei Liu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China
| | - Ying Xu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China
| | - Hongbo Shen
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China
| | - Jingran Yan
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China
| | - Enzhuo Yang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China
| | - Honghai Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, P.R. China
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12
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Immunohistochemical expression of interferon-γ in different types of granulomatous lesions associated with bovine paratuberculosis. Comp Immunol Microbiol Infect Dis 2017; 51:1-8. [DOI: 10.1016/j.cimid.2017.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/23/2016] [Accepted: 01/03/2017] [Indexed: 11/19/2022]
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13
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Abstract
Infections with Mycobacterium tuberculosis (MTB) induce complex immune responses involving an orchestrated interplay of innate and adaptive immune mechanisms. Why the immune system fails to eradicate the pathogen and at best achieves control of infection in the latent stage, still remains an unsolved mystery even more than 100 years after the discovery of MTB by Robert Koch. This article provides an overview of the current state of the art in the constantly evolving field of tuberculosis (TB) immunology. This review focuses on a change of paradigm proposing that in the latent stage MTB is anything but dormant and that latent TB is not merely a state of bacterial stasis but a state of dynamic bacterial and immunological equilibrium. The understanding of these dynamics is crucial for the development of new drugs against MTB as well as vaccines that aim to provide effective protection against the disease.
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Affiliation(s)
- A Nowag
- Klinik I für Innere Medizin, Uniklinik Köln, Gleueler Str. 129-131, Gebäude 57, 50937, Köln, Deutschland
| | - P Hartmann
- Klinik I für Innere Medizin, Uniklinik Köln, Gleueler Str. 129-131, Gebäude 57, 50937, Köln, Deutschland. .,Zentrale Krankenhaushygiene, Uniklinik Köln, Gleueler Str. 129-131, Gebäude 57, 50937, Köln, Deutschland.
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14
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Pesce A, Bustamante JP, Bidon-Chanal A, Boechi L, Estrin DA, Luque FJ, Sebilo A, Guertin M, Bolognesi M, Ascenzi P, Nardini M. The N-terminal pre-A region of Mycobacterium tuberculosis 2/2HbN promotes NO-dioxygenase activity. FEBS J 2015; 283:305-22. [PMID: 26499089 DOI: 10.1111/febs.13571] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 08/09/2015] [Accepted: 08/16/2015] [Indexed: 01/24/2023]
Abstract
UNLABELLED A unique defense mechanisms by which Mycobacterium tuberculosis protects itself from nitrosative stress is based on the O2 -dependent NO-dioxygenase (NOD) activity of truncated hemoglobin 2/2HbN (Mt2/2HbN). The NOD activity largely depends on the efficiency of ligand migration to the heme cavity through a two-tunnel (long and short) system; recently, it was also correlated with the presence at the Mt2/2HbN N-terminus of a short pre-A region, not conserved in most 2/2HbNs, whose deletion results in a drastic reduction of NO scavenging. In the present study, we report the crystal structure of Mt2/2HbN-ΔpreA, lacking the pre-A region, at a resolution of 1.53 Å. We show that removal of the pre-A region results in long range effects on the protein C-terminus, promoting the assembly of a stable dimer, both in the crystals and in solution. In the Mt2/2HbN-ΔpreA dimer, access of heme ligands to the short tunnel is hindered. Molecular dynamics simulations show that the long tunnel branch is the only accessible pathway for O2 -ligand migration to/from the heme, and that the gating residue Phe(62)E15 partly restricts the diameter of the tunnel. Accordingly, kinetic measurements indicate that the kon value for peroxynitrite isomerization by Mt2/2HbN-ΔpreA-Fe(III) is four-fold lower relative to the full-length protein, and that NO scavenging by Mt2/2HbN-ΔpreA-Fe(II)-O2 is reduced by 35-fold. Therefore, we speculate that Mt2/2HbN evolved to host the pre-A region as a mechanism for preventing dimerization, thus reinforcing the survival of the microorganism against the reactive nitrosative stress in macrophages. DATABASE Coordinates and structure factors have been deposited in the Protein Data Bank under accession number 5AB8.
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Affiliation(s)
| | - Juan P Bustamante
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Argentina
| | - Axel Bidon-Chanal
- Departament de Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, University of Barcelona, Santa Coloma de Gramenet, Spain
| | - Leonardo Boechi
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Argentina
| | - Darío A Estrin
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Argentina
| | - Francisco Javier Luque
- Departament de Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, University of Barcelona, Santa Coloma de Gramenet, Spain
| | - Anne Sebilo
- Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Quebec, Canada
| | - Michel Guertin
- Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Quebec, Canada
| | - Martino Bolognesi
- Department of Biosciences, University of Milan, Italy.,CNR-IBF and CIMAINA, University of Milan, Italy
| | - Paolo Ascenzi
- Interdepartmental Laboratory of Electron Microscopy, Roma Tre University, Rome, Italy.,National Institute of Biostructures and Biosystems, Rome, Italy
| | - Marco Nardini
- Department of Biosciences, University of Milan, Italy
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Travar M, Petkovic M, Verhaz A. Type I, II, and III Interferons: Regulating Immunity to Mycobacterium tuberculosis Infection. Arch Immunol Ther Exp (Warsz) 2015; 64:19-31. [PMID: 26362801 DOI: 10.1007/s00005-015-0365-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/22/2015] [Indexed: 01/18/2023]
Abstract
Interferons (IFNs) are cytokines released by host cells in response to the presence of pathogens or tumor cells. The aim of this review was to present the previously known and new findings about the role of interferons type I and II, and recently discovered type III in Mycobacterium tuberculosis (M. tuberculosis) infection control. Infection of various cell types with M. tuberculosis induce both IFN-α and IFN-β synthesis. The majority of the studies support the findings that IFN type I actually promotes infection with M. tuberculosis. It has been well establish that IFN-γ has protective function against M. tuberculosis and the other mycobacteria and that the primary source of this cytokine are CD4(+) and CD8(+) T cells. Recently, it has been shown that also the innate lymphocytes, γδ T cells, natural killer (NK) T cells, and NK cells can also be the source of IFN-γ in response to mycobacterial infection. Several studies have shown that CD4(+) T cells protect mice against M. tuberculosis independently of IFN-γ. The balance between IFN-γ and different cytokines such as IL-10 and other Th2 cell cytokines is likely to influence disease outcome. Type I IFN appears to be detrimental through at least three separate, but overlapping, type I IFN-mediated mechanisms: induction of excessive apoptosis, specific suppression of Th1 and IFN-γ responses, and dampening of the immune response by strong IL-10 induction. Recently it has been found that M. tuberculosis infection in A549 lung epithelial cells stimulate up-regulation of IFN-λ genes in vitro. IFN-λs also have a role in modulation of Th1/Th2 response. IFN-λs are not essential for M. tuberculosis infection control, but can give some contribution in immune response to this pathogen.
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Affiliation(s)
- Maja Travar
- Department of Microbiology, University Hospital Clinical Centre Banja Luka, Banja Luka, Republic of Srpska, Bosnia and Herzegovina. .,Department of Microbiology and Immunology, Faculty of Medicine, Banja Luka University, Banja Luka, Republic of Srpska, Bosnia and Herzegovina.
| | - Miroslav Petkovic
- Department of Microbiology and Immunology, Faculty of Medicine, Banja Luka University, Banja Luka, Republic of Srpska, Bosnia and Herzegovina
| | - Antonija Verhaz
- Clinic for Infectious Diseases, University Hospital Clinical Centre Banja Luka, Banja Luka, Republic of Srpska, Bosnia and Herzegovina
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16
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Orme IM, Robinson RT, Cooper AM. The balance between protective and pathogenic immune responses in the TB-infected lung. Nat Immunol 2015; 16:57-63. [PMID: 25521685 DOI: 10.1038/ni.3048] [Citation(s) in RCA: 182] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 11/05/2014] [Indexed: 01/01/2023]
Abstract
Tuberculosis is a disease of the lung, and efficient transmission is dependent on the generation of a lesion in the lung, which results in a bacterium-laden cough. Mycobacterium tuberculosis (Mtb) is able to manipulate both the innate and acquired immune response of the host. This manipulation results in an effective CD4(+) T cell response that limits disease throughout the body but can also promote the development of progressively destructive lesions in the lung. In this way Mtb infection can result in an ambulatory individual who has a lesion in the lung capable of transmitting Mtb. The inflammatory environment within the lung lesion is manipulated by Mtb throughout infection and can limit the expression of acquired immunity by a variety of pathways.
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Affiliation(s)
- Ian M Orme
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Richard T Robinson
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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17
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Rottenberg ME, Carow B. SOCS3 and STAT3, major controllers of the outcome of infection with Mycobacterium tuberculosis. Semin Immunol 2014; 26:518-32. [DOI: 10.1016/j.smim.2014.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 01/04/2023]
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18
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da Costa AC, Costa-Júnior ADO, de Oliveira FM, Nogueira SV, Rosa JD, Resende DP, Kipnis A, Junqueira-Kipnis AP. A new recombinant BCG vaccine induces specific Th17 and Th1 effector cells with higher protective efficacy against tuberculosis. PLoS One 2014; 9:e112848. [PMID: 25398087 PMCID: PMC4232451 DOI: 10.1371/journal.pone.0112848] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/15/2014] [Indexed: 01/08/2023] Open
Abstract
Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) that is a major public health problem. The vaccine used for TB prevention is Mycobacterium bovis bacillus Calmette-Guérin (BCG), which provides variable efficacy in protecting against pulmonary TB among adults. Consequently, several groups have pursued the development of a new vaccine with a superior protective capacity to that of BCG. Here we constructed a new recombinant BCG (rBCG) vaccine expressing a fusion protein (CMX) composed of immune dominant epitopes from Ag85C, MPT51, and HspX and evaluated its immunogenicity and protection in a murine model of infection. The stability of the vaccine in vivo was maintained for up to 20 days post-vaccination. rBCG-CMX was efficiently phagocytized by peritoneal macrophages and induced nitric oxide (NO) production. Following mouse immunization, this vaccine induced a specific immune response in cells from lungs and spleen to the fusion protein and to each of the component recombinant proteins by themselves. Vaccinated mice presented higher amounts of Th1, Th17, and polyfunctional specific T cells. rBCG-CMX vaccination reduced the extension of lung lesions caused by challenge with Mtb as well as the lung bacterial load. In addition, when this vaccine was used in a prime-boost strategy together with rCMX, the lung bacterial load was lower than the result observed by BCG vaccination. This study describes the creation of a new promising vaccine for TB that we hope will be used in further studies to address its safety before proceeding to clinical trials.
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Affiliation(s)
- Adeliane Castro da Costa
- Laboratório de Imunopatologia das Doenças Infecciosas, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Abadio de Oliveira Costa-Júnior
- Laboratório de Imunopatologia das Doenças Infecciosas, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Fábio Muniz de Oliveira
- Laboratório de Bacteriologia Molecular, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Sarah Veloso Nogueira
- Laboratório de Imunopatologia das Doenças Infecciosas, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Joseane Damaceno Rosa
- Laboratório de Imunopatologia das Doenças Infecciosas, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Danilo Pires Resende
- Laboratório de Imunopatologia das Doenças Infecciosas, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - André Kipnis
- Laboratório de Bacteriologia Molecular, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Ana Paula Junqueira-Kipnis
- Laboratório de Imunopatologia das Doenças Infecciosas, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
- * E-mail:
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19
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Orchestration of pulmonary T cell immunity during Mycobacterium tuberculosis infection: immunity interruptus. Semin Immunol 2014; 26:559-77. [PMID: 25311810 DOI: 10.1016/j.smim.2014.09.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/17/2014] [Accepted: 09/19/2014] [Indexed: 12/31/2022]
Abstract
Despite the introduction almost a century ago of Mycobacterium bovis BCG (BCG), an attenuated form of M. bovis that is used as a vaccine against Mycobacterium tuberculosis, tuberculosis remains a global health threat and kills more than 1.5 million people each year. This is mostly because BCG fails to prevent pulmonary disease--the contagious form of tuberculosis. Although there have been significant advances in understanding how the immune system responds to infection, the qualities that define protective immunity against M. tuberculosis remain poorly characterized. The ability to predict who will maintain control over the infection and who will succumb to clinical disease would revolutionize our approach to surveillance, control, and treatment. Here we review the current understanding of pulmonary T cell responses following M. tuberculosis infection. While infection elicits a strong immune response that contains infection, M. tuberculosis evades eradication. Traditionally, its intracellular lifestyle and alteration of macrophage function are viewed as the dominant mechanisms of evasion. Now we appreciate that chronic inflammation leads to T cell dysfunction. While this may arise as the host balances the goals of bacterial sterilization and avoidance of tissue damage, it is becoming clear that T cell dysfunction impairs host resistance. Defining the mechanisms that lead to T cell dysfunction is crucial as memory T cell responses are likely to be subject to the same subject to the same pressures. Thus, success of T cell based vaccines is predicated on memory T cells avoiding exhaustion while at the same time not promoting overt tissue damage.
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20
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Abstract
The mouse provides a tool with which to probe the complex interaction between the mammalian immune system and the slow-growing, inflammatory, and persistent bacterium, Mycobacterium tuberculosis (Mtb). Simple mouse models using genetic deletion or antibody inhibition have identified causal connections between specific components of the immune response and survival upon challenge with Mtb, and these studies have corresponded with observations made in humans. To improve on current intervention strategies, it is essential that the complex interactions between the components of the immune response that mediate and regulate the protective response to Mtb infection be dissected; furthermore, the pathways by which specific molecules and cells act must be delineated. The mouse model provides a tool with which to achieve this goal; however, experimental design and data interpretation must be made in the context of data sets generated from the entire tuberculosis field.
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21
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IL-10 and NOS2 modulate antigen-specific reactivity and nerve infiltration by T cells in experimental leprosy. PLoS Negl Trop Dis 2014; 8:e3149. [PMID: 25210773 PMCID: PMC4161319 DOI: 10.1371/journal.pntd.0003149] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/28/2014] [Indexed: 12/18/2022] Open
Abstract
Background Although immunopathology dictates clinical outcome in leprosy, the dynamics of early and chronic infection are poorly defined. In the tuberculoid region of the spectrum, Mycobacterium leprae growth is restricted yet a severe granulomatous lesion can occur. The evolution and maintenance of chronic inflammatory processes like those observed in the leprosy granuloma involve an ongoing network of communications via cytokines. IL-10 has immunosuppressive properties and IL-10 genetic variants have been associated with leprosy development and reactions. Methodology/Principal Findings The role of IL-10 in resistance and inflammation in leprosy was investigated using Mycobacterium leprae infection of mice deficient in IL-10 (IL-10−/−), as well as mice deficient in both inducible nitric oxide synthase (NOS2−/−) and IL-10 (10NOS2−/−). Although a lack of IL-10 did not affect M. leprae multiplication in the footpads (FP), inflammation increased from C57Bl/6 (B6)<IL-10−/−<NOS2−/−<10NOS2−/−. While IL-10−/− mice exhibited modest FP induration compared to B6, NOS2−/− and 10NOS2−/− mice developed markedly enlarged FP marking distinct phases: early (1 month), peak (3–4 months), and chronic (8 months). IFN-γ-producing CD4+CD44+ cells responding to M. leprae cell wall, membrane, and cytosol antigens and ML2028 (Ag85B) were significantly increased in the evolved granuloma in NOS2−/− FP compared to B6 and IL-10−/− during early and peak phases. In 10NOS2−/− FP, CD4+CD44+ and especially CD8+CD44+ responses were augmented even further to these antigens as well as to ML0380 (GroES), ML2038 (bacterioferritin), and ML1877 (EF-Tu). Moreover, fragmented nerves containing CD4+ cells were present in 10NOS2−/− FP. Conclusions/Significance The 10NOS2−/− strain offers insight on the regulation of granuloma formation and maintenance by immune modulators in the resistant forms of leprosy and presents a new model for investigating the pathogenesis of neurological involvement. Despite effective antimicrobial therapy, 30–50% of leprosy patients develop immunological complications called leprosy reactions before, during or even years after being cured. Leprosy reactions are a major risk for neuritis that leads to peripheral nerve damage, disfigurement and disability. Unfortunately, why and how leprosy reactions occur is not well understood. Based on the latest human genetic leprosy susceptibility research and mouse infection models, we generated a double knockout mouse strain (10NOS2−/−) which has deficiencies in two key immune factors, interleukin-10 (IL-10) and inducible nitric oxide synthase (NOS2). We investigated the dynamics of the immune response to Mycobacterium leprae infection and chronicled the types of immune cells recruited to the site of infection. 10NOS2−/− mice developed a substantial induration in response to infection, as well as an increased interferon-gamma response to components of the leprosy bacillus. Interestingly, these animals also exhibited CD4+ T cell infiltration into the nerves, a phenomenon which has not been previously reported in leprosy mouse models. This new model provides insight into potential mechanisms whereby immune modulators may regulate leprosy reactions and neuritis and could aid the development of tests for monitoring and treatment of leprosy patients.
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22
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Prozorov AA, Fedorova IA, Bekker OB, Danilenko VN. The virulence factors of Mycobacterium tuberculosis: Genetic control, new conceptions. RUSS J GENET+ 2014. [DOI: 10.1134/s1022795414080055] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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Li M, Wang H, Wang X, Huang J, Wang J, Xi X. Diagnostic accuracy of tumor necrosis factor-alpha, interferon-gamma, interleukin-10 and adenosine deaminase 2 in differential diagnosis between tuberculous pleural effusion and malignant pleural effusion. J Cardiothorac Surg 2014; 9:118. [PMID: 24984978 PMCID: PMC4227019 DOI: 10.1186/1749-8090-9-118] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 05/05/2014] [Indexed: 11/10/2022] Open
Abstract
Background The current study was performed to investigate the potential biomarkers for the differential diagnosis of tuberculous pleural effusion (TPE) and malignant pleural effusions (MPE). Methods Among ninety patients (n = 90) involved in the study, 47 with tuberculous pleural effusion aged from 18 to 70 and 43 with secondary malignant pleural effusion aged from 34 to 78. We tested the pleural levels of TNF-α, IFN-γ and IL-10 as well as the enzyme activity of ADA2, and then we compared the differential diagnostic efficiencies of those biochemical parameters with ADA between the two groups. Results Our results show that, the concentrations of pleural TNF-α (45.55 ± 15.85 ng/L), IFN-γ (114.97 ± 27.85 ng/L) as well as activities of ADA2 (35.71 ± 10.00 U/L) and ADA (39.39 ± 10.60 U/L) in tuberculous group were significantly higher compared to malignant group. Furthermore, according to the ROC curve analysis the thresholds of TNF-α, IFN-γ, ADA2 and ADA were found to be 30.3 ng/L, 103.65 ng/L, 29.45 U/L, and 39.00 U/L, respectively. TNF-α, IFN-γ and ADA2 yielded better sensitivity, specificity, and accuracy of the diagnosis than ADA. Our investigation further revealed that the combinations of TNF-α and ADA2 further increased the specificity and accuracy for the differential diagnosis. Conclusion In conclusion, we found that TNF-α, IFN-γ, ADA and ADA2 all increased in TPE. Combinations of the TNF-α and ADA2 yielded the best specificity and accuracy for the differential diagnosis of TPE from MPE. Our investigation suggests that the applications of TNF-α together with ADA2 may contribute to more efficient diagnosis strategies in the management of discrimination between tuberculous and malignant pleural effusions.
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Affiliation(s)
| | | | | | | | | | - Xiue Xi
- The First Affiliated Hospital of Xinxiang Medical University, No,88 Jiankang Road, Weihui 453100, Henan Province, China.
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24
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Abstract
Small size globins that have been defined as 'truncated haemoglobins' or as '2/2 haemoglobins' have increasingly been discovered in microorganisms since the early 1990s. Analysis of amino acid sequences allowed to distinguish three groups that collect proteins with specific and common structural properties. All three groups display 3D structures that are based on four main α-helices, which are a subset of the conventional eight-helices globin fold. Specific features, such as the presence of protein matrix tunnels that are held to promote diffusion of functional ligands to/from the haem, distinguish members of the three groups. Haem distal sites vary for their accessibility, local structures, polarity, and ligand stabilization mechanisms, suggesting functional roles that are related to O2/NO chemistry. In a few cases, such activities have been proven in vitro and in vivo through deletion mutants. The issue of 2/2 haemoglobin varied biological functions throughout the three groups remains however fully open.
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de Martino M, Galli L, Chiappini E. Reflections on the immunology of tuberculosis: will we ever unravel the skein? BMC Infect Dis 2014; 14 Suppl 1:S1. [PMID: 24564297 PMCID: PMC4015689 DOI: 10.1186/1471-2334-14-s1-s1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Many and large dumps exist in our knowledge about Mycobacterium tuberculosis infection and disease in infants and children. We still do not understand why some individuals do acquire and others do not acquire the infection in the presence of the same risk factors. We do not understand why some individuals convert from latent to active tuberculosis and why other individuals convert from active to inactive tuberculosis even without treatment. As a matter of fact the immune system mounts a bouncing, robust and polyedral defence against Mycobacterium tuberculosis, but the bacillus is so much artful and dextrous that it has ahead from this immunological fierce accoutrements. Mycobacterium tuberculosis survival, multiplication, and transmission are largely favoured by the immune mechanisms. The granuloma itself is more bacillus- than host-protective. These abilities make Mycobacterium tuberculosis one of more successful human pathogens, but dumps in our knowledge and the counterproductive immunity hinder development of new diagnostics, therapies and vaccines. This occurs in front of an infection which engages one third of the world population and a disease which kills in a year about 1.5 million individuals worldwide. Understanding mechanisms and meaning of immune response in tuberculosis marks out the foundations of strategies with a view to prepare effective vaccines and reliable diagnostic tools as well as to build up therapeutic weapons. To gain these objectives is vital and urgent considering that tuberculosis is a common cause of morbidity and is a leading cause of death.
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du Plessis N, Walzl G. Helminth-M. tb co-infection. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 828:49-74. [PMID: 25253027 DOI: 10.1007/978-1-4939-1489-0_3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Nelita du Plessis
- Biomedical Sciences, Division Molecular Biology and Human Genetics, DST/NRF, Centre of Excellence in Biomedical TB Research, Stellenbosch University, Cape Town, Western Cape, South Africa,
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27
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Adams LB, Pena MT, Sharma R, Hagge DA, Schurr E, Truman RW. Insights from animal models on the immunogenetics of leprosy: a review. Mem Inst Oswaldo Cruz 2013; 107 Suppl 1:197-208. [PMID: 23283472 DOI: 10.1590/s0074-02762012000900028] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 06/05/2012] [Indexed: 11/21/2022] Open
Abstract
A variety of host immunogenetic factors appear to influence both an individual's susceptibility to infection with Mycobacterium leprae and the pathologic course of the disease. Animal models can contribute to a better understanding of the role of immunogenetics in leprosy through comparative studies helping to confirm the significance of various identified traits and in deciphering the underlying mechanisms that may be involved in expression of different disease related phenotypes. Genetically engineered mice, with specific immune or biochemical pathway defects, are particularly useful for investigating granuloma formation and resistance to infection and are shedding new light on borderline areas of the leprosy spectrum which are clinically unstable and have a tendency toward immunological complications. Though armadillos are less developed in this regard, these animals are the only other natural hosts of M. leprae and they present a unique opportunity for comparative study of genetic markers and mechanisms associable with disease susceptibility or resistance, especially the neurological aspects of leprosy. In this paper, we review the recent contributions of genetically engineered mice and armadillos toward our understanding of the immunogenetics of leprosy.
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Affiliation(s)
- Linda B Adams
- Department of Health and Human Services, Health Resources and Services Administration, Bureau of Primary Health Care, National Hansen's Disease Programs, Baton Rouge, LA, USA.
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28
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Torrado E, Cooper AM. Cytokines in the balance of protection and pathology during mycobacterial infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 783:121-40. [PMID: 23468107 DOI: 10.1007/978-1-4614-6111-1_7] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The outcome of natural infections with pathogenic mycobacteria can range from early asymptomatic clearance through latent infection to clinical disease. Different host and pathogen-specific factors have been implicated in determining the outcome of these infections; however, it is clear that the interaction of mycobacteria with the innate and acquired components of the immune system plays a central role. Specifically, the recognition of mycobacterial components by innate immune cells through different pathogen recognition receptors (PPRs) induces a cytokine response that can promote early control of the infection. In fact, in the majority of individuals that come into contact with mycobacteria, this response is enough to control the infection. Among PRRs, Toll-like receptors (TLRs), Nucleotide Oligomerization Domain (NOD)-like receptors, and C-type lectins have all been implicated in recognition of mycobacteria and in the initiation of the cytokine response. Defining the mechanisms by which distinct mycobacterial components and their receptors stimulate the immune response is an area of intense research.
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O'Garra A, Redford PS, McNab FW, Bloom CI, Wilkinson RJ, Berry MPR. The immune response in tuberculosis. Annu Rev Immunol 2013; 31:475-527. [PMID: 23516984 DOI: 10.1146/annurev-immunol-032712-095939] [Citation(s) in RCA: 907] [Impact Index Per Article: 82.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
There are 9 million cases of active tuberculosis reported annually; however, an estimated one-third of the world's population is infected with Mycobacterium tuberculosis and remains asymptomatic. Of these latent individuals, only 5-10% will develop active tuberculosis disease in their lifetime. CD4(+) T cells, as well as the cytokines IL-12, IFN-γ, and TNF, are critical in the control of Mycobacterium tuberculosis infection, but the host factors that determine why some individuals are protected from infection while others go on to develop disease are unclear. Genetic factors of the host and of the pathogen itself may be associated with an increased risk of patients developing active tuberculosis. This review aims to summarize what we know about the immune response in tuberculosis, in human disease, and in a range of experimental models, all of which are essential to advancing our mechanistic knowledge base of the host-pathogen interactions that influence disease outcome.
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Affiliation(s)
- Anne O'Garra
- Division of Immunoregulation, MRC National Institute for Medical Research, London NW7 1AA, UK.
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30
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Bottasso O, Bay ML, Besedovsky H, Del Rey A. Adverse neuro-immune-endocrine interactions in patients with active tuberculosis. Mol Cell Neurosci 2012; 53:77-85. [PMID: 23147110 DOI: 10.1016/j.mcn.2012.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 11/01/2012] [Accepted: 11/02/2012] [Indexed: 12/21/2022] Open
Abstract
The nervous, endocrine and immune systems play a crucial role in maintaining homeostasis and interact with each other for a successful defensive strategy against injurious agents. However, the situation is different in long-term diseases with marked inflammation, in which defensive mechanisms become altered. In the case of tuberculosis (TB), this is highlighted by several facts: an imbalance of plasma immune and endocrine mediators, that results in an adverse environment for mounting an adequate response against mycobacteria and controlling inflammation; the demonstration that dehidroepiandrosterone (DHEA) secretion by a human adrenal cell line can be inhibited by culture supernatants from Mycobacterium tuberculosis-stimulated peripheral blood mononuclear cells - PBMC - of TB patients, with this effect being partly reverted when neutralizing transforming growth factor-β in such supernantants; the in vitro effects of adrenal steroids on the specific immune response of PBMC from TB patients, that is a cortisol inhibition of mycobacterial antigen-driven lymphoproliferation and interferon-γ production as well as a suppression of TGF-β production in DHEA-treated PBMC; and lastly the demonstration that immune and endocrine compounds participating in the regulation of energy sources and immune activity correlated with the consumption state of TB patients. Collectively, immune-endocrine disturbances of TB patients are involved in critical components of disease pathology with implications in the impaired clinical status and unfavorable disease outcome. This article is part of a Special Issue entitled 'Neuroinflammation in neurodegeneration and neurodysfunction'.
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Affiliation(s)
- Oscar Bottasso
- Instituto de Inmunología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Argentina.
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31
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Abebe F. Is interferon-gamma the right marker for bacille Calmette-Guérin-induced immune protection? The missing link in our understanding of tuberculosis immunology. Clin Exp Immunol 2012; 169:213-9. [PMID: 22861360 DOI: 10.1111/j.1365-2249.2012.04614.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Bacille Calmette-Guérin (BCG), developed a century ago, is the only licensed tuberculosis (TB) vaccine in use to date. The protective efficacy of BCG against TB varies with no apparent protection in some population, and mechanisms of its immune protection is poorly known, and yet BCG is the most widely used vaccine, with more than 4 billion BCG-vaccinated children globally. BCG is probably the only licensed vaccine currently in use believed to mediate immune protection through the production of interferon (IFN)-γ by CD4 T cells, which in turn activates macrophages to kill Mycobacterium tuberculosis (Mtb). Currently, a number of new TB candidate vaccines are in different phases of clinical trial. The majority of these new vaccines are either recombinant forms of BCG or prime boosters of BCG (rBCG) and their immunogenicity is tested using BCG as a benchmark by measuring specific IFN-γ produced by CD4(+) T cells as a protective immune marker. However, some recent studies that examined mechanisms of immune protection of BCG in animals and humans have reported a lack of correlation between IFN-γ production by CD4 cells and BCG-induced immune protection. These studies point to the fact that there is a missing link in our understanding of TB immunology. Conversely, there is emerging evidence that other T cell subsets (gammadelta, γδ), CD8(+) T cells and natural killer (NK) cells may play a vital role in immune protection against Mtb infection and BCG-induced immune protection. γδ T cells and NK cells, which were considered to be part of the innate immunity in the past, have been shown to develop immunological memory upon re-encounter with the same pathogen. In this paper, the controversy over the role of IFN-γ as a marker for protective immunity against TB, and emerging data on the role of γδ T cells, CD8(+) and NK cells in TB immunology, will be presented.
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Affiliation(s)
- F Abebe
- Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway.
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32
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Pearl JE, Torrado E, Tighe M, Fountain JJ, Solache A, Strutt T, Swain S, Appelberg R, Cooper AM. Nitric oxide inhibits the accumulation of CD4+CD44hiTbet+CD69lo T cells in mycobacterial infection. Eur J Immunol 2012; 42:3267-79. [PMID: 22890814 DOI: 10.1002/eji.201142158] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 06/27/2012] [Accepted: 08/10/2012] [Indexed: 12/18/2022]
Abstract
Animals lacking the inducible nitric oxide synthase gene (nos2(-/-)) are less susceptible to Mycobacterium avium strain 25291 and lack nitric oxide-mediated immunomodulation of CD4(+) T cells. Here we show that the absence of nos2 results in increased accumulation of neutrophils and both CD4(+) and CD8(+) T cells within the M. avium containing granuloma. Examination of the T-cell phenotype in M. avium infected mice demonstrated that CD4(+)CD44(hi) effector T cells expressing the Th1 transcriptional regulator T-bet (T-bet(+)) were specifically reduced by the presence of nitric oxide. Importantly, the T-bet(+) effector population could be separated into CD69(hi) and CD69(lo) populations, with the CD69(lo) population only able to accumulate during chronic infection within infected nos2(-/-) mice. Transcriptomic comparison between CD4(+)CD44(hi)CD69(hi) and CD4(+)CD44(hi)CD69(lo) populations revealed that CD4(+)CD44(hi)CD69(lo) cells had higher expression of the integrin itgb1/itga4 (VLA-4, CD49d/CD29). Inhibition of Nos2 activity allowed increased accumulation of the CD4(+) CD44(hi)T-bet(+)CD69(lo) population in WT mice as well as increased expression of VLA-4. These data support the hypothesis that effector T cells in mycobacterial granulomata are not a uniform effector population but exist in distinct subsets with differential susceptibility to the regulatory effects of nitric oxide.
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Affiliation(s)
- John E Pearl
- Trudeau Institute Inc, Saranac Lake, NY 12983, USA
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33
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Munawwar A, Singh S. AIDS associated tuberculosis: a catastrophic collision to evade the host immune system. Tuberculosis (Edinb) 2012; 92:384-7. [PMID: 22795795 DOI: 10.1016/j.tube.2012.05.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 03/04/2012] [Accepted: 05/11/2012] [Indexed: 02/07/2023]
Abstract
Human immunodeficiency virus (HIV) is a causative agent of AIDS while Mycobacterium tuberculosis causes human tuberculosis, independently. HIV and M. tuberculosis co-infection is an intriguing immunopathological phenomenon. The effect is not simply an additive but far more than that. This review gives an account of how various host and pathogen specific factors interplay to make this co-infection one of the worst co-infection, rightly named as medical "double jeopardy". We have attempted to recount some of the immune mechanisms how both these pathogens disturb the balance of host immune system resulting into defects in the host phagocytic response, leading to apoptosis and chemokine dysregulation. The HIV provides protected shelter to the M. tuberculosis and M. tuberculosis provides conducive atmosphere through the interplay of various chemokines. We also touch upon the treatment associated complications like Immune reconstitution inflammatory syndrome (IRIS) these patients face.
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Affiliation(s)
- Arshi Munawwar
- Division of Clinical Microbiology, All India Institute of Medical Sciences, New Delhi 110029, India
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Borges M, Barreira-Silva P, Flórido M, Jordan MB, Correia-Neves M, Appelberg R. Molecular and cellular mechanisms of Mycobacterium avium-induced thymic atrophy. THE JOURNAL OF IMMUNOLOGY 2012; 189:3600-8. [PMID: 22922815 DOI: 10.4049/jimmunol.1201525] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Thymic atrophy has been described as a consequence of infection by several pathogens and shown to be induced through diverse mechanisms. Using the mouse model of Mycobacterium avium infection, we show in this study that the production of NO from IFN-γ-activated macrophages plays a major role in mycobacterial infection-induced thymic atrophy. Our results show that disseminated infection with a highly virulent strain of M. avium, but not with a low-virulence strain, led to a progressive thymic atrophy. Thymic involution was prevented in genetically manipulated mice unable to produce IFN-γ or the inducible NO synthase. In addition, mice with a selective impairment of IFN-γ signaling in macrophages were similarly protected from infection-induced thymic atrophy. A slight increase in the concentration of corticosterone was found in mice infected with the highly virulent strain, and thymocytes presented an increased susceptibility to dexamethasone-induced death during disseminated infection. The administration of an antagonist of glucocorticoid receptors partially reverted the infection-induced thymic atrophy. We observed a reduction in all thymocyte populations analyzed, including the earliest thymic precursors, suggesting a defect during thymic colonization by T cell precursors and/or during the differentiation of these cells in the bone marrow in addition to local demise of thymic cells. Our data suggest a complex picture underlying thymic atrophy during infection by M. avium with the participation of locally produced NO, endogenous corticosteroid activity, and reduced bone marrow seeding.
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Affiliation(s)
- Margarida Borges
- Institute for Molecular and Cell Biology, University of Porto, 4150-180 Porto, Portugal
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35
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Zhang Q, Sugawara I. Immunology of tuberculosis. World J Exp Med 2012; 2:70-4. [PMID: 24520536 PMCID: PMC3905591 DOI: 10.5493/wjem.v2.i4.70] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 04/05/2012] [Accepted: 07/27/2012] [Indexed: 02/06/2023] Open
Abstract
Various T cells and macrophages as well as cytokines are involved in the immunopathogenesis of tuberculosis (TB). A better understanding of immunology of TB can not only lead to the discovery of new immunodiagnostic tools, accelerate and facilitate the assessment of new therapeutic methods, but also find new treatment regimens. In this highlight topic we cover the latest developments in the role of T cells, macrophages, Natural killer (NK) cells, invariant NK T (iNKT) cells and γδ T cells with TB infection. Histologically, TB displays exudative inflammation, proliferative inflammation and productive inflammation depending on the time course. T cells first recognize antigen within the mycobacterially-infected lung, and then activate, differentiate, but the first T cell activation occurs in the draining lymph nodes of the lung. When protective T cells reach sufficient numbers, they can stop bacterial growth. Except for T cells, neutrophils also participate actively in defense against early-phase TB. NK cells are innate lymphocytes which are a first line of defense against mycobacterial infection. Human NK cells use the NKp46, NCRs and NKG2D receptors to lyse Mycobacterium TB-infected monocytes and alveolar macrophages. NK cells produce not only interferon-γ, but also interleukin (IL)-22, which is induced by IL-15 and DAP-10. iNKT cells show different phenotypes and functions. Many iNKT cells are CD4+, few iNKT cells are CD8+, while an additional fraction of iNKT cells are negative for both CD4 and CD8. γδ T cells represent an early innate defense in antimycobacterial immunity. Studies done in humans and animal models have demonstrated complex patterns of γδ T cell immune responses during chronic TB. Human alveolar macrophages and monocytes can serve as antigen presentation cells for γδ T cells. Furthermore, the predominance of Vγ9Vδ2 T cells in TB has been confirmed.
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Affiliation(s)
- Qing Zhang
- Qing Zhang, Isamu Sugawara, Center of Tuberculosis Diagnosis and Treatment, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Isamu Sugawara
- Qing Zhang, Isamu Sugawara, Center of Tuberculosis Diagnosis and Treatment, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
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36
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Cellular and humoral mechanisms involved in the control of tuberculosis. Clin Dev Immunol 2012; 2012:193923. [PMID: 22666281 PMCID: PMC3362816 DOI: 10.1155/2012/193923] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/06/2012] [Accepted: 03/06/2012] [Indexed: 02/08/2023]
Abstract
Mycobacterium tuberculosis (Mtb) infection is a major international public health problem. One-third of the world's population is thought to have latent tuberculosis, a condition where individuals are infected by the intracellular bacteria without active disease but are at risk for reactivation, if their immune system fails. Here, we discuss the role of nonspecific inflammatory responses mediated by cytokines and chemokines induced by interaction of innate receptors expressed in macrophages and dendritic cells (DCs). We also review current information regarding the importance of several cytokines including IL-17/IL-23 in the development of protective cellular and antibody-mediated protective responses against Mtb and their influence in containment of the infection. Finally, in this paper, emphasis is placed on the mechanisms of failure of Mtb control, including the immune dysregulation induced by the treatment with biological drugs in different autoimmune diseases. Further functional studies, focused on the mechanisms involved in the early host-Mtb interactions and the interplay between host innate and acquired immunity against Mtb, may be helpful to improve the understanding of protective responses in the lung and in the development of novel therapeutic and prophylactic tools in TB.
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37
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Nandi B, Behar SM. Regulation of neutrophils by interferon-γ limits lung inflammation during tuberculosis infection. ACTA ACUST UNITED AC 2011; 208:2251-62. [PMID: 21967766 PMCID: PMC3201199 DOI: 10.1084/jem.20110919] [Citation(s) in RCA: 261] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
IFN-γ functions to suppress neutrophil accumulation in the lungs of mice infected with M. tuberculosis, in part by suppressing IL-17 production from CD4+ T cells. Resistance to Mycobacterium tuberculosis requires the host to restrict bacterial replication while preventing an over-exuberant inflammatory response. Interferon (IFN) γ is crucial for activating macrophages and also regulates tissue inflammation. We dissociate these two functions and show that IFN-γ−/− memory CD4+ T cells retain their antimicrobial activity but are unable to suppress inflammation. IFN-γ inhibits CD4+ T cell production of IL-17, which regulates neutrophil recruitment. In addition, IFN-γ directly inhibits pathogenic neutrophil accumulation in the infected lung and impairs neutrophil survival. Regulation of neutrophils is important because their accumulation is detrimental to the host. We suggest that neutrophilia during tuberculosis indicates failed Th1 immunity or loss of IFN-γ responsiveness. These results establish an important antiinflammatory role for IFN-γ in host protection against tuberculosis.
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Affiliation(s)
- Bisweswar Nandi
- Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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38
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Impact of toll-like receptor 2 deficiency on immune responses to mycobacterial antigens. Infect Immun 2011; 79:4649-56. [PMID: 21844233 DOI: 10.1128/iai.05724-11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In the present study, we addressed the question of whether Toll-like receptor 2 (TLR2)-mediated innate immunity can contribute to the development of acquired immune responses. We immunized TLR2(-/-) and wild-type (WT) mice three times subcutaneously with the mycobacterial antigen (Ag19kDa) (a TLR2 ligand) or Ag85A (not a TLR2 ligand). One week after the last immunization, sera and spleens were collected. To evaluate cellular responses, we measured gamma interferon (IFN-γ) after in vitro restimulation of spleen cells with antigen alone or antigen-pulsed bone marrow-derived macrophages (BMM(Ag)) or pulmonary macrophages (PuM(Ag)). Antibody responses were comparable in the two mouse strains, but we observed differences in the cellular responses. Recall responses to Ag85A were similar in the two strains, but responses to Ag19kDa given alone or presented by BMM or PuM were lower in TLR2(-/-) than in WT mice. The largest differences in cellular responses were observed when Ag19kDa was presented by PuM. To understand this, we analyzed phenotypic and functional differences between BMM and PuM upon stimulation with various ligands. Generally, PuM had a lower response to the TLR2 ligand Pam(3)Cys-Ser-(Lys)(4) trihydrochloride and to anti-CD40 than BMM, as measured by cytokine secretion and upregulation of costimulatory molecules. This might provide a partial explanation for the lower capacity of PuM when pulsed with Ag19kDa, also a TLR2 ligand. Altogether, our results revealed weaknesses in the T cell and antigen-presenting cell (APC) compartments of the Ag19kDa-immunized TLR2(-/-) mice but indicated that specific immune responses could be generated in the absence of TLR2 regardless of the characteristics of the antigen used.
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39
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Zhang J, Qian X, Ning H, Eickhoff CS, Hoft DF, Liu J. Transcriptional suppression of IL-27 production by Mycobacterium tuberculosis-activated p38 MAPK via inhibition of AP-1 binding. THE JOURNAL OF IMMUNOLOGY 2011; 186:5885-95. [PMID: 21482740 DOI: 10.4049/jimmunol.1003447] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mycobacterium tuberculosis remains a major global challenge to human health care, and the mechanisms of how M. tuberculosis evades host immune surveillance to favor its survival are still largely unknown. In this study, we found that bacillus Calmette-Guérin (BCG) and viable M. tuberculosis as well as M. tuberculosis lysates could activate IL-27 expression in human and mouse macrophages by induction of p28 subunit transcription. However, in parallel with these effects, BCG and M. tuberculosis lysate stimulation of macrophages induced activation of p38 MAPK signaling molecules MLK3/MKK3/MK2 to prevent maximal IL-27 production. M. tuberculosis lysate-induced p28 transcription was dependent on MyD88 signaling pathway. AP-1/c-Fos was shown to bind directly to the p28 promoter and induce p28 expression after M. tuberculosis lysate stimulation. Overexpression of p38α inhibited the binding of c-Fos to the p28 promoter but had no effect on c-Fos protein expression or phosphorylation in response to M. tuberculosis lysate stimulation. Furthermore, blockade of p38 by SB203580 enhanced M. tuberculosis-induced AP-1 binding to the p28 promoter. Importantly, we show that adding exogenous IL-27 to increase the levels produced by PBMCs stimulated with live mycobacteria enhanced the ability of BCG-expanded T cells to inhibit intracellular mycobacterial growth in human macrophages. Taken together, our data demonstrate that mycobacterial stimulation induces both IL-27 production and p38 MAPK activation. Strategies designed to tip the balance toward positive regulation of p28 induction by mycobacteria could lead to enhanced protective tuberculosis immunity.
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Affiliation(s)
- Jidong Zhang
- Division of Infectious Diseases, Allergy, and Immunology, Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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40
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D'Attilio L, Trini E, Bongiovanni B, Dídoli G, Gardeñez W, Nannini LJ, Giri A, Bottasso OA, Bay ML. mRNA expression of alpha and beta isoforms of glucocorticoid receptor in peripheral blood mononuclear cells of patients with tuberculosis and its relation with components of the immunoendocrine response. Brain Behav Immun 2011; 25:461-7. [PMID: 21093577 DOI: 10.1016/j.bbi.2010.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 10/31/2010] [Accepted: 11/10/2010] [Indexed: 12/22/2022] Open
Abstract
We have analyzed the expression of glucocorticoid receptor (GR) isoforms by real time RT-qPCR in PBMCs from 19 controls (HCo) and 28 TB patients (8 mild; 12 moderate; 8 severe), HIV(-) and similar sex and age distribution. mRNA hGRα/β ratios were found higher in TB patients respect to those in HCo. However, when analyzing for disease severity such overall trend was at the expense of mild and moderate patients, with severe cases showing a lower mRNA hGRα/β ratio with respect to the other patient groups. This suggested some degree of resistance to endogenous glucocorticoids in patients with severe TB, since hGRαα dimer mediates the biological functions of GC, with the GRβ isoform acting as an inhibitor of GC activity. Levels of IL-6, IL-18, IFN-γ and Cortisol were significantly increased in severe and moderate cases, whereas DHEA values were found decreased in them (p<0.05 respect to HCo). Analysis on the relationship between plasma levels of these immuno-endocrine mediators with the mRNA expression of hGRα and hGRβ showed that IL-6 was positively associated with hGRα in mild TB patients (p<0.01), whereas a negative correlation between IFN-γ and hGRβ was observed in severe cases (p<0.01). As regard to hormones, DHEA was positively associated with hGRα in moderate and severe cases (p<0.01). This group also showed a negative correlation between hGRα and Cortisol/DHEA ratios (p<0.05). Changes in the systemic levels of cytokine and adrenal hormones are likely to affect GR expression in a differential fashion and according to the amount of pulmonary involvement.
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Affiliation(s)
- Luciano D'Attilio
- Instituto de Inmunología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, 2000 Rosario, Argentina
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41
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Toll-like receptor 9 is required for full host resistance to Mycobacterium avium infection but plays no role in induction of Th1 responses. Infect Immun 2011; 79:1638-46. [PMID: 21300776 DOI: 10.1128/iai.01030-10] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
To investigate the role of Toll-like receptor 9 (TLR9) in innate immunity to Mycobacterium avium, TLR9, TLR2, and MyD88 knockout (KO) mice were infected with this bacterium. Bacterial burdens were higher in the spleens, livers, and lungs of infected TLR9 KO mice than in those of C57BL/6 mice, indicating that TLR9 is required for efficient control of M. avium infection. However, TLR9 KO or TLR2 KO spleen cells displayed normal M. avium-induced tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) responses. This finding was confirmed by determining the number of splenic CD4(+) T cells producing IFN-γ by flow cytometry. Furthermore, TLR2 and MyD88, but not TLR9, played a major role in interleukin-12 and TNF-α production by M. avium-infected macrophages and dendritic cells (DCs). We also found that major histocompatibility complex class II molecule expression on DCs is regulated by TLR2 and MyD88 signaling but not by TLR9. Finally, lack of TLR9, TLR2, or MyD88 reduced the numbers of macrophages, epithelioid cells, and lymphocytes in M. avium-induced granulomas but only MyD88 deficiency affected the number of liver granulomas. In summary, our data demonstrated that the involvement of TLR9 in the control of M. avium infection is not related to the induction of Th1 responses.
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42
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Cellular response to mycobacteria: balancing protection and pathology. Trends Immunol 2011; 32:66-72. [PMID: 21216195 DOI: 10.1016/j.it.2010.12.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 12/03/2010] [Accepted: 12/06/2010] [Indexed: 12/31/2022]
Abstract
There has been a recent increase in our understanding of T cell responses during mycobacterial infection; however, we have not yet identified the protective mechanisms capable of mediating vaccine-induced protection in the lung. Novel approaches have allowed the determination of the kinetics and location of naïve T cell activation, as well as the factors that affect of antigen-specific T cell responses, and the balance between protective and immunopathological consequences during the chronic stages of infection. With an urgent need for new and more efficient vaccination strategies, the integration of these data will result in improved vaccine strategies.
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43
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Mycobacteria-induced suppression of autoimmunity in the central nervous system. J Neuroimmune Pharmacol 2010; 5:210-9. [PMID: 20333556 DOI: 10.1007/s11481-010-9199-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
Abstract
Mycobacterial suppression of central nervous system (CNS) autoimmunity has been demonstrated in various experimental models, epidemiological studies, and clinical trials. Recent studies have led to an increased understanding of the cellular and molecular interactions involved in the pathogenesis of autoimmune diseases and of mycobacterial immunity. Here, we review some of the mechanisms by which mycobacterial infection might modulate the clinical course of CNS autoimmunity. A more complete understanding of these mechanisms may lead to the development of novel immunotherapeutic tools for treating autoimmune diseases.
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44
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Silva MT. Neutrophils and macrophages work in concert as inducers and effectors of adaptive immunity against extracellular and intracellular microbial pathogens. J Leukoc Biol 2010; 87:805-13. [PMID: 20110444 DOI: 10.1189/jlb.1109767] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Emerging data suggest new facets of the concerted participation of neutrophils and macrophages in antimicrobial immunity. The classical view is that DCs and macrophages are the inducers of adaptive antimicrobial immunity, but there is evidence for neutrophil participation in this task as cytokine and chemokine producers and APCs. On the other hand, the concept that the T(H)1 response is only associated with control of infections by intracellular pathogens through activation of macrophages by IFN-gamma, and the T(H)17/IL-17 axis is only involved in protection against extracellular pathogens through mobilization and activation of neutrophils is simplistic: There is evidence suggesting that T(H)1 and T(H)17 responses, separately or in parallel, may use macrophages and neutrophils against infections by extracellular and intracellular microbial pathogens. Opsonization by pathogen-specific Igs enhances the antimicrobial capabilities of neutrophils and macrophages in infections by extracellular and intracellular microbes. The functional partnership between macrophages and neutrophils as inducers and effectors of adaptive antimicrobial immunity conforms to their affiliation with the myeloid phagocyte system and reveals a strategy based on the concurrent use of the two professional phagocytes in the adaptive defense mechanisms. Starting from a common myeloid precursor in the bone marrow, macrophages and neutrophils split during differentiation but come together at the infectious foci for a cooperative strategy that uses modulator and effector activities to attack invading microbial pathogens.
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Affiliation(s)
- Manuel T Silva
- Instituto de Biologia Molecular e Celular, Porto, Portugal.
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45
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Wolfe DN, Karanikas AT, Hester SE, Kennett MJ, Harvill ET. IL-10 induction by Bordetella parapertussis limits a protective IFN-gamma response. THE JOURNAL OF IMMUNOLOGY 2009; 184:1392-400. [PMID: 20042578 DOI: 10.4049/jimmunol.0803045] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bordetella parapertussis causes the prolonged coughing illness known as pertussis or whooping cough, persisting for weeks within the respiratory tracts of infected hosts but inducing a very poor T cell response relative to that induced by Bordetella pertussis, the more common cause of pertussis. In this study, we examine the contributions of cytokines involved in the clearance of B. parapertussis and immunomodulation that delays effective clearance. The slow elimination of this pathogen from the respiratory tracts of mice coincides with the gradual accumulation of CD4(+) T cells in the lungs and B. parapertussis-responsive IFN-gamma-producing cells in the spleen. IFN-gamma-deficient mice were defective in the accumulation of leukocytes in lungs and in clearance of B. parapertussis from the lungs. In vitro B. parapertussis-stimulated macrophages produced IL-10, which inhibited the generation of the IFN-gamma response that is required for protection in vivo. As compared with wild-type mice, IL-10-deficient mice produced significantly higher levels of IFN-gamma, had higher numbers of leukocytes accumulated in the lungs, and cleared B. parapertussis more rapidly. Together, these data indicate that B. parapertussis induces the production of IL-10, which facilitates its persistence within infected hosts by limiting a protective IFN-gamma response.
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Affiliation(s)
- Daniel N Wolfe
- Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA 16802, USA
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46
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Vaccination with the ML0276 antigen reduces local inflammation but not bacterial burden during experimental Mycobacterium leprae infection. Infect Immun 2009; 77:5623-30. [PMID: 19786561 DOI: 10.1128/iai.00508-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Leprosy elimination has been a goal of the WHO for the past 15 years. Widespread BCG vaccination and multidrug therapy have dramatically reduced worldwide leprosy prevalence, but new case detection rates have remained relatively constant. These data suggest that additional control strategies, such as a subunit vaccine, are required to block transmission and to improve leprosy control. We recently identified several Mycobacterium leprae antigens that stimulate gamma interferon (IFN-gamma) secretion upon incubation with blood from paucibacillary leprosy patients, a group who limit M. leprae growth and dissemination. In this study, we demonstrate that M. leprae-specific mouse T-cell lines recognize several of these antigens, with the ML0276 protein stimulating the most IFN-gamma secretion. We then examined if the ML0276 protein could be used in a subunit vaccine to provide protection against experimental M. leprae infection. Our data demonstrate that combining ML0276 with either a Toll-like receptor 4 (TLR4) (EM005), TLR7 (imiquimod), or TLR9 (CpG DNA) agonist during immunization induces Th1 responses that limit local inflammation upon experimental M. leprae infection. Our data indicate that only the ML0276/EM005 regimen is able to elicit a response that is transferable to recipient mice. Despite the potent Th1 response induced by this regimen, it could not provide protection in terms of limiting bacterial growth. We conclude that EM005 is the most potent adjuvant for stimulating a Th1 response and indicate that while a subunit vaccine containing the ML0276 protein may be useful for the prevention of immune pathology during leprosy, it will not control bacterial burden and is therefore unlikely to interrupt disease transmission.
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Fc receptor-targeted mucosal vaccination as a novel strategy for the generation of enhanced immunity against mucosal and non-mucosal pathogens. Arch Immunol Ther Exp (Warsz) 2009; 57:311-23. [PMID: 19688186 DOI: 10.1007/s00005-009-0040-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 03/30/2009] [Indexed: 12/22/2022]
Abstract
Numerous studies have demonstrated that targeting immunogens to Fcgamma receptors (FcgammaR) on antigen (Ag)-presenting cells (APC) can enhance humoral and cellular immunity in vitro and in vivo. FcgammaR are classified based on their molecular weight, IgG-Fc binding affinities, IgG subclass binding specificity, and cellular distribution and they consist of activating and inhibitory receptors. However, despite the potential advantages of targeting Ag to FcR at mucosal sites, very little is known regarding the role of FcR in mucosal immunity or the efficacy of FcR-targeted mucosal vaccines. In addition, recent work has suggested that FcRn is present in the lungs of adult mice and humans and can transport FcRn-targeted Ag to FcgammaR-bearing APC within mucosal lymphoid tissue. In this review we will discuss the need for new vaccine strategies, the potential for FcR-targeted vaccines to fill this need, the impact of activating versus inhibitory FcgammaR on FcR-targeted vaccination, the significance of focusing on mucosal immunity, as well as caveats that could impact the use of FcR targeting as a mucosal vaccine strategy.
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48
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Greco KN, Mendonça RMZ, Moraes RHP, Mancini DAP, Mendonça RZ. Antiviral activity of the hemolymph of Lonomia obliqua (Lepidoptera: Saturniidae). Antiviral Res 2009; 84:84-90. [PMID: 19665487 DOI: 10.1016/j.antiviral.2009.07.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 07/27/2009] [Accepted: 07/29/2009] [Indexed: 12/25/2022]
Abstract
Potent antiviral activity against measles, influenza and polio viruses was observed in the hemolymph of Lonomia obliqua. The antiviral protein responsible for this activity was isolated, purified by gel filtration chromatography using a gel filtration column system (Superdex 75) and further fractionated using a Resource-Q ion exchange column system. Experiments with the purified protein led to a 157-fold reduction (from 3.3+/-1.25 x 10(7) to 2.1+/-1.5 x 10(5) TCID(50)mL(-1)) in measles virus production and a 61-fold reduction (from 2.8+/-1.08 x 10(9) to 4.58+/-1.42 x 10(7)mL(-1)) in polio virus production. Heating and freezing seem to have no influence over its antiviral activity. Also, the protein does not display virucidal activity and does not act on receptors on the cell membrane. The observations suggest an intracellular mechanism of action and that the protein may act as a constitutive agent that affects the innate antiviral immune response.
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Affiliation(s)
- Katia N Greco
- Laboratório de Parasitologia e Entomologia, Instituto Butantan, São Paulo, Brazil
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49
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Cooper AM. T cells in mycobacterial infection and disease. Curr Opin Immunol 2009; 21:378-84. [PMID: 19646851 DOI: 10.1016/j.coi.2009.06.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 05/12/2009] [Accepted: 06/27/2009] [Indexed: 11/27/2022]
Abstract
There has been an increase in our understanding of the complexity of the T cell response to mycobacterial infection recently. Improved tools have allowed the determination of the location and kinetics of naïve T cell activation in the mouse as well the variety of function of mycobacteria-specific cells in humans. There is also an increased appreciation of the balance required during mycobacterial infection between anti-bacterial activity and control of the immunopathologic response. The integration of the T cell functional data with the consequences of infection should improve rational vaccine design.
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Abstract
Tuberculosis is primarily a disease of the lung, and dissemination of the disease depends on productive infection of this critical organ. Upon aerosol infection with Mycobacterium tuberculosis (Mtb), the acquired cellular immune response is slow to be induced and to be expressed within the lung. This slowness allows infection to become well established; thus, the acquired response is expressed in an inflammatory site that has been initiated and modulated by the bacterium. Mtb has a variety of surface molecules that interact with the innate response, and this interaction along with the autoregulation of the immune response by several mechanisms results in less-than-optimal control of bacterial growth. To improve current vaccine strategies, we must understand the factors that mediate induction, expression, and regulation of the immune response in the lung. We must also determine how to induce both known and novel immunoprotective responses without inducing immunopathologic consequences.
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