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Effects of helminths and Mycobacterium tuberculosis infection on HIV-1: a cellular immunological perspective. Curr Opin HIV AIDS 2012; 7:260-7. [PMID: 22411452 DOI: 10.1097/coh.0b013e3283521144] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW In many regions of the world, a high prevalence of HIV-1, helminthic and Mycobacterium tuberculosis (Mtb) infections can be found. Here, we summarize the types of immune responses induced and/or modulated by these pathogens and the consequences for HIV-1 disease. RECENT FINDINGS Helminths predominantly induce strong T helper (Th) 2 cellular responses which are downregulated in chronic disease. The anatomical niche populated by helminths plays a key factor in the effect these parasites have on HIV-1 transmission and subsequent replication. Gut-associated helminths have been found to increase HIV-1 transmission via the lesions they provide. In spite of this, the many immune modulatory molecules secreted by the parasites may inhibit or slow HIV-1 infection. In contrast, Mtb is mainly restricted to the lung and the Mtb-specific Th cells induced are highly susceptible to HIV-1 infection and replication. Antigens from both pathogens have immunomodulatory activity that can skew cellular immune responses in specific directions. SUMMARY The effect of helminths and Mtb on modulating immune responses is varied and complex with both their location and phenotype potentially influencing HIV-1 disease. These pathogens have evolved a complex array of molecules which have the capacity to modulate immunity and preserve pathogen survival.
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102
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Bold TD, Ernst JD. CD4+ T cell-dependent IFN-γ production by CD8+ effector T cells in Mycobacterium tuberculosis infection. THE JOURNAL OF IMMUNOLOGY 2012; 189:2530-6. [PMID: 22837486 DOI: 10.4049/jimmunol.1200994] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Both CD4+ and CD8+ T cells contribute to immunity to tuberculosis, and both can produce the essential effector cytokine IFN-γ. However, the precise role and relative contribution of each cell type to in vivo IFN-γ production are incompletely understood. To identify and quantitate the cells that produce IFN-γ at the site of Mycobacterium tuberculosis infection in mice, we used direct intracellular cytokine staining ex vivo without restimulation. We found that CD4+ and CD8+ cells were predominantly responsible for production of this cytokine in vivo, and we observed a remarkable linear correlation between the fraction of CD4+ cells and the fraction of CD8+ cells producing IFN-γ in the lungs. In the absence of CD4+ cells, a reduced fraction of CD8+ cells was actively producing IFN-γ in vivo, suggesting that CD4+ effector cells are continually required for optimal IFN-γ production by CD8+ effector cells. Accordingly, when infected mice were treated i.v. with an MHC-II-restricted M. tuberculosis epitope peptide to stimulate CD4+ cells in vivo, we observed rapid activation of both CD4+ and CD8+ cells in the lungs. Indirect activation of CD8+ cells was dependent on the presence of CD4+ cells but independent of IFN-g responsiveness of the CD8+ cells. These data provide evidence that CD4+ cell deficiency impairs IFN-γ production by CD8+ effector cells and that ongoing cross-talk between distinct effector T cell types in the lungs may contribute to a protective immune response against M. tuberculosis. Conversely, defects in these interactions may contribute to susceptibility to tuberculosis and other infections.
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Affiliation(s)
- Tyler D Bold
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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103
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104
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The HyVac4 subunit vaccine efficiently boosts BCG-primed anti-mycobacterial protective immunity. PLoS One 2012; 7:e39909. [PMID: 22768165 PMCID: PMC3386939 DOI: 10.1371/journal.pone.0039909] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 06/02/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The current vaccine against tuberculosis (TB), BCG, has failed to control TB worldwide and the protective efficacy is moreover limited to 10-15 years. A vaccine that could efficiently boost a BCG-induced immune response and thus prolong protective immunity would therefore have a significant impact on the global TB-burden. METHODS/FINDINGS In the present study we show that the fusion protein HyVac4 (H4), consisting of the mycobacterial antigens Ag85B and TB10.4, given in the adjuvant IC31® or DDA/MPL effectively boosted and prolonged immunity induced by BCG, leading to improved protection against infection with virulent M. tuberculosis (M.tb). Increased protection correlated with an increased percentage of TB10.4 specific IFNγ/TNFα/IL-2 or TNFα/IL-2 producing CD4 T cells at the site of infection. Moreover, this vaccine strategy did not compromise the use of ESAT-6 as an accurate correlate of disease development/vaccine efficacy. Indeed both CD4 and CD8 ESAT-6 specific T cells showed significant correlation with bacterial levels. CONCLUSIONS/SIGNIFICANCE H4-IC31® can efficiently boost BCG-primed immunity leading to an increased protective anti-M.tb immune response dominated by IFNγ/TNFα/IL-2 or TNFα/IL2 producing CD4 T cells. H4 in the CD4 T cell inducing adjuvant IC31® is presently in clinical trials.
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105
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Immune markers and correlates of protection for vaccine induced immune responses. Vaccine 2012; 30:4907-20. [PMID: 22658928 DOI: 10.1016/j.vaccine.2012.05.049] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/15/2012] [Accepted: 05/19/2012] [Indexed: 12/15/2022]
Abstract
Vaccines have been a major innovation in the history of mankind and still have the potential to address the challenges posed by chronic intracellular infections including tuberculosis, HIV and malaria which are leading causes of high morbidity and mortality across the world. Markers of an appropriate humoral response currently remain the best validated correlates of protective immunity after vaccination. Despite advancements in the field of immunology over the past few decades currently there are, however, no sufficiently validated immune correlates of vaccine induced protection against chronic infections in neither human nor veterinary medicine. Technological and conceptual advancements within cell-mediated immunology have led to a number of new immunological read-outs with the potential to emerge as correlates of vaccine induced protection. For T(H)1 type responses, antigen-specific production of interferon-gamma (IFN-γ) has been promoted as a quantitative marker of protective cell-mediated immune responses over the past couple of decades. More recently, however, evidence from several infections has pointed towards the quality of the immune response, measured through increased levels of antigen-specific polyfunctional T cells capable of producing a triad of relevant cytokines, as a better correlate of sustained protective immunity against this type of infections. Also the possibilities to measure antigen-specific cytotoxic T cells (CTL) during infection or in response to vaccination, through recombinant major histocompatibility complex (MHC) class I tetramers loaded with relevant peptides, has opened a new vista to include CTL responses in the evaluation of protective immune responses. Here, we review different immune markers and new candidates for correlates of a protective vaccine induced immune response against chronic infections and how successful they have been in defining the protective immunity in human and veterinary medicine.
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106
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Cooper AM, Torrado E. Protection versus pathology in tuberculosis: recent insights. Curr Opin Immunol 2012; 24:431-7. [PMID: 22613092 DOI: 10.1016/j.coi.2012.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 04/30/2012] [Indexed: 01/23/2023]
Abstract
Recent studies have revisited the roles of prime players in the immune response to tuberculosis (TB) and have highlighted novel functions of these players. Specifically, immunoregulatory mechanisms mediated by IFNγ have been delineated as well as a novel role for neutrophils in promoting antigen presentation. New insights into the interaction between the bacterium and phagocyte indicate that the bacterium actively promotes phagocyte necrosis rather than apoptosis and that this impacts generation of the acquired response. There are also many new examples of how the phagocyte responds to the bacteria and how it mediates control. The phenotype of protective T cells is also being re-examined. These developments provide promise for improved vaccine design and highlight the complexity of this disease.
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Affiliation(s)
- Andrea M Cooper
- The Trudeau Institute, Inc. 154 Algonquin Ave., Saranac Lake, NY 12983, United States.
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107
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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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108
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Blomgran R, Desvignes L, Briken V, Ernst JD. Mycobacterium tuberculosis inhibits neutrophil apoptosis, leading to delayed activation of naive CD4 T cells. Cell Host Microbe 2012; 11:81-90. [PMID: 22264515 DOI: 10.1016/j.chom.2011.11.012] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/31/2011] [Accepted: 11/30/2011] [Indexed: 02/06/2023]
Abstract
Mycobacterium tuberculosis promotes its replication by inhibiting the apoptosis of infected macrophages. A proapoptotic M. tuberculosis mutant lacking nuoG, a subunit of the type I NADH dehydrogenase complex, exhibits attenuated growth in vivo, indicating that this virulence mechanism is essential. We show that M. tuberculosis also suppresses neutrophil apoptosis. Compared to wild-type, the nuoG mutant spread to a larger number of lung phagocytic cells. Consistent with the shorter lifespan of infected neutrophils, infection with the nuoG mutant resulted in fewer bacteria per infected neutrophil, accelerated bacterial acquisition by dendritic cells, earlier trafficking of these dendritic cells to lymph nodes, and faster CD4 T cell priming. Neutrophil depletion abrogated accelerated CD4 T cell priming by the nuoG mutant, suggesting that inhibiting neutrophil apoptosis delays adaptive immunity in tuberculosis. Thus, pathogen modulation of apoptosis is beneficial at multiple levels, and enhancing phagocyte apoptosis promotes CD4 as well as CD8 T cell responses.
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Affiliation(s)
- Robert Blomgran
- Division of Infectious Diseases, Department of Medicine, New York University School of Medicine, New York, NY 10016, USA
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109
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Ramakrishnan L. Revisiting the role of the granuloma in tuberculosis. Nat Rev Immunol 2012; 12:352-66. [PMID: 22517424 DOI: 10.1038/nri3211] [Citation(s) in RCA: 544] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The granuloma, which is a compact aggregate of immune cells, is the hallmark structure of tuberculosis. It is historically regarded as a host-protective structure that 'walls off' the infecting mycobacteria. This Review discusses surprising new discoveries--from imaging studies coupled with genetic manipulations--that implicate the innate immune mechanisms of the tuberculous granuloma in the expansion and dissemination of infection. It also covers why the granuloma can fail to eradicate infection even after adaptive immunity develops. An understanding of the mechanisms and impact of tuberculous granuloma formation can guide the development of therapies to modulate granuloma formation. Such therapies might be effective for tuberculosis as well as for other granulomatous diseases.
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Affiliation(s)
- Lalita Ramakrishnan
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA.
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110
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Bold TD, Davis DC, Penberthy KK, Cox LM, Ernst JD, de Jong BC. Impaired fitness of Mycobacterium africanum despite secretion of ESAT-6. J Infect Dis 2012; 205:984-90. [PMID: 22301632 PMCID: PMC3282571 DOI: 10.1093/infdis/jir883] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Accepted: 10/28/2011] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND When compared with Mycobacterium tuberculosis, individuals that live in the same household as an active case of smear-positive pulmonary tuberculosis exposed to M. africanum progress less frequently to active disease within 2 years. A putative ESX-1 secretion apparatus member, Rv3879c, is mutated in M. africanum, and individuals infected with M. africanum less frequently demonstrate T-cell responses to the ESX-1-secreted virulence factor ESAT-6 than those infected with M. tuberculosis. We hypothesized that less frequent progression is caused by impaired secretion of ESAT-6. METHODS We analyzed in vivo growth and in vitro secretion of ESAT-6 and CFP-10, comparing M. tuberculosis to M. africanum and a strain of M. africanum complemented with M. tuberculosis Rv3879c. RESULTS ESAT-6 and CFP-10 secretion were similar for all strains, although these were enriched in M. africanum cell lysates, suggesting a modest ESX-1 secretion defect unrelated to the Rv3879c mutation. In mice, M. africanum demonstrated smaller bacterial population sizes than M. tuberculosis but similar numbers and frequencies of ESAT-6-responsive T cells in the lungs. CONCLUSIONS These results confirm impaired fitness of M. africanum in vivo and indicate that Rv3879c is not required for secretion of ESAT-6 or for its presentation as an antigen to T cells in vivo.
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Affiliation(s)
| | | | | | - Laura M. Cox
- Department of Medicine, Division of Infectious Diseases
| | - Joel D. Ernst
- Department of Medicine, Division of Infectious Diseases
- Department of Pathology
- Department of Microbiology, New York University School of Medicine, New York
| | - Bouke C. de Jong
- Department of Medicine, Division of Infectious Diseases
- Institute of Tropical Medicine, Antwerp, Belgium
- Medical Research Council Laboratories, The Gambia
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111
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Lee SJ, McLachlan JB, Kurtz JR, Fan D, Winter SE, Baumler AJ, Jenkins MK, McSorley SJ. Temporal expression of bacterial proteins instructs host CD4 T cell expansion and Th17 development. PLoS Pathog 2012; 8:e1002499. [PMID: 22275869 PMCID: PMC3262010 DOI: 10.1371/journal.ppat.1002499] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 12/07/2011] [Indexed: 01/09/2023] Open
Abstract
Pathogens can substantially alter gene expression within an infected host depending on metabolic or virulence requirements in different tissues, however, the effect of these alterations on host immunity are unclear. Here we visualized multiple CD4 T cell responses to temporally expressed proteins in Salmonella-infected mice. Flagellin-specific CD4 T cells expanded and contracted early, differentiated into Th1 and Th17 lineages, and were enriched in mucosal tissues after oral infection. In contrast, CD4 T cells responding to Salmonella Type-III Secretion System (TTSS) effectors steadily accumulated until bacterial clearance was achieved, primarily differentiated into Th1 cells, and were predominantly detected in systemic tissues. Thus, pathogen regulation of antigen expression plays a major role in orchestrating the expansion, differentiation, and location of antigen-specific CD4 T cells in vivo.
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Affiliation(s)
- Seung-Joo Lee
- Center for Comparative Medicine, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - James B. McLachlan
- Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
- Department of Microbiology & Immunology, Tulane University Health Science Center, New Orleans, Louisiana, United States of America
| | - Jonathan R. Kurtz
- Department of Microbiology & Immunology, Tulane University Health Science Center, New Orleans, Louisiana, United States of America
| | - Danhua Fan
- Department of Biostatistics and Informatics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Sebastian E. Winter
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Andreas J. Baumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Marc K. Jenkins
- Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Stephen J. McSorley
- Center for Comparative Medicine, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
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Nambiar JK, Pinto R, Aguilo JI, Takatsu K, Martin C, Britton WJ, Triccas JA. Protective immunity afforded by attenuated, PhoP-deficient Mycobacterium tuberculosis is associated with sustained generation of CD4+ T-cell memory. Eur J Immunol 2011; 42:385-92. [PMID: 22105536 DOI: 10.1002/eji.201141903] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 09/30/2011] [Accepted: 11/15/2011] [Indexed: 11/07/2022]
Abstract
Definition of protective immunity induced by effective vaccines is important for the design of new pathogen control strategies. Inactivation of the PhoP response-regulator in Mycobacterium tuberculosis results in a highly attenuated strain that demonstrates impressive protective efficacy in pre-clinical models of tuberculosis. In this report we demonstrate that the protection afforded by the M. tuberculosis phoP mutant strain is associated with the long-term maintenance of CD4(+) T-cell memory. Immunization of mice with SO2 resulted in enhanced expansion of M. tuberculosis-specific CD4(+) T cells compared with vaccination with the BCG vaccine, with an increased frequency of these cells persisting at extended time-points after vaccination. Strikingly, vaccination with SO2 resulted in sustained generation of CD4(+) T cells displaying a central memory phenotype, a property not shared by BCG. Further, SO2 vaccination markedly improved the generation of polyfunctional cytokine-secreting CD4(+) T cells compared with BCG vaccination. The improved generation of functionally competent memory T cells by SO2 correlated with augmented recall responses in SO2-vaccinated animals after challenge with virulent M. tuberculosis. This study defines a mechanism for the protective effect of the SO2 vaccine and suggests that deletion of defined virulence networks may provide vaccine strains with potent immuno-stimulatory properties.
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Affiliation(s)
- Jonathan K Nambiar
- Microbial Pathogenesis and Immunity Group, Discipline of Infectious Diseases and Immunology, University of Sydney, Sydney, Australia
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Romano M, Aryan E, Korf H, Bruffaerts N, Franken CLMC, Ottenhoff THM, Huygen K. Potential of Mycobacterium tuberculosis resuscitation-promoting factors as antigens in novel tuberculosis sub-unit vaccines. Microbes Infect 2011; 14:86-95. [PMID: 21920450 DOI: 10.1016/j.micinf.2011.08.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 08/10/2011] [Accepted: 08/21/2011] [Indexed: 01/18/2023]
Abstract
Novel vaccines are needed to control tuberculosis (TB), the bacterial infectious disease that together with malaria and HIV is worldwide responsible for high levels of morbidity and mortality. TB can result from the reactivation of an initially controlled latent infection by Mycobacterium tuberculosis (Mtb). Mtb proteins for which a possible role in this reactivation process has been hypothesized are the five homologs of the resuscitation-promoting factor of Micrococcus luteus, namely Mtb Rv0867c (rpfA), Rv1009 (rpfB), Rv1884c (rpfC), Rv2389c (rpfD) and Rv2450c (rpfE). Analysis of the immune recognition of these 5 proteins following Mtb infection or Mycobacterium bovis BCG vaccination of mice showed that Rv1009 (rpfB) and Rv2389c (rpfD) are the most antigenic in the tested models. We therefore selected rpfB and rpfD for testing their vaccine potential as plasmid DNA vaccines. Elevated cellular immune responses and modest but significant protection against intra-tracheal Mtb challenge were induced by immunization with the rpfB encoding DNA vaccine. The results indicate that rpfB is the most promising candidate of the five rpf-like proteins of Mtb in terms of its immunogenicity and protective efficacy and warrants further analysis for inclusion as an antigen in novel TB vaccines.
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Affiliation(s)
- M Romano
- Scientific Institute of Public Health (WIV-ISP), Scientific Service Immunology, 642 Engelandstraat, B-1180 Brussels, Belgium.
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114
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Affiliation(s)
- Egidio Torrado
- Trudeau Institute, Inc., Saranac Lake, New York, United States of America
| | - Andrea M. Cooper
- Trudeau Institute, Inc., Saranac Lake, New York, United States of America
- * E-mail:
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