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Nicole JA, Iván GA. Inmunopatogenia de las enfermedades autoinmunes. REVISTA MÉDICA CLÍNICA LAS CONDES 2012. [DOI: 10.1016/s0716-8640(12)70337-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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202
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Maieron A, Kerschner H. Teicoplanin therapy leading to a significant decrease in viral load in a patient with chronic hepatitis C. J Antimicrob Chemother 2012; 67:2537-8. [PMID: 22687891 PMCID: PMC7109765 DOI: 10.1093/jac/dks217] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Andreas Maieron
- Gastroenterology and Hepatology, Elisabethinen Hospital, Fadingerstrasse 1, 4020 Linz, Austria
| | - Heidrun Kerschner
- Institute for Hygiene, Microbiology and Tropical Medicine, Elisabethinen Hospital, Fadingerstrasse 1, 4020 Linz, Austria
- Corresponding author. Tel: +43-732-7676-3689; Fax: +43-732-7676-3686; E-mail:
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203
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Young GR, Ploquin MJY, Eksmond U, Wadwa M, Stoye JP, Kassiotis G. Negative selection by an endogenous retrovirus promotes a higher-avidity CD4+ T cell response to retroviral infection. PLoS Pathog 2012; 8:e1002709. [PMID: 22589728 PMCID: PMC3349761 DOI: 10.1371/journal.ppat.1002709] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 04/04/2012] [Indexed: 11/18/2022] Open
Abstract
Effective T cell responses can decisively influence the outcome of retroviral infection. However, what constitutes protective T cell responses or determines the ability of the host to mount such responses is incompletely understood. Here we studied the requirements for development and induction of CD4+ T cells that were essential for immunity to Friend virus (FV) infection of mice, according to their TCR avidity for an FV-derived epitope. We showed that a self peptide, encoded by an endogenous retrovirus, negatively selected a significant fraction of polyclonal FV-specific CD4+ T cells and diminished the response to FV infection. Surprisingly, however, CD4+ T cell-mediated antiviral activity was fully preserved. Detailed repertoire analysis revealed that clones with low avidity for FV-derived peptides were more cross-reactive with self peptides and were consequently preferentially deleted. Negative selection of low-avidity FV-reactive CD4+ T cells was responsible for the dominance of high-avidity clones in the response to FV infection, suggesting that protection against the primary infecting virus was mediated exclusively by high-avidity CD4+ T cells. Thus, although negative selection reduced the size and cross-reactivity of the available FV-reactive naïve CD4+ T cell repertoire, it increased the overall avidity of the repertoire that responded to infection. These findings demonstrate that self proteins expressed by replication-defective endogenous retroviruses can heavily influence the formation of the TCR repertoire reactive with exogenous retroviruses and determine the avidity of the response to retroviral infection. Given the overabundance of endogenous retroviruses in the human genome, these findings also suggest that endogenous retroviral proteins, presented by products of highly polymorphic HLA alleles, may shape the human TCR repertoire that reacts with exogenous retroviruses or other infecting pathogens, leading to interindividual heterogeneity.
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Affiliation(s)
- George R. Young
- Division of Immunoregulation, MRC National Institute for Medical Research, London, United Kingdom
| | - Mickaël J.-Y. Ploquin
- Division of Immunoregulation, MRC National Institute for Medical Research, London, United Kingdom
| | - Urszula Eksmond
- Division of Immunoregulation, MRC National Institute for Medical Research, London, United Kingdom
| | - Munisch Wadwa
- Division of Immunoregulation, MRC National Institute for Medical Research, London, United Kingdom
| | - Jonathan P. Stoye
- Division of Virology, MRC National Institute for Medical Research, London, United Kingdom
| | - George Kassiotis
- Division of Immunoregulation, MRC National Institute for Medical Research, London, United Kingdom
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204
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Chen AT, Cornberg M, Gras S, Guillonneau C, Rossjohn J, Trees A, Emonet S, de la Torre JC, Welsh RM, Selin LK. Loss of anti-viral immunity by infection with a virus encoding a cross-reactive pathogenic epitope. PLoS Pathog 2012; 8:e1002633. [PMID: 22536152 PMCID: PMC3334890 DOI: 10.1371/journal.ppat.1002633;ppathogens-d-11-02190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
T cell cross-reactivity between different strains of the same virus, between different members of the same virus group, and even between unrelated viruses is a common occurrence. We questioned here how an intervening infection with a virus containing a sub-dominant cross-reactive T cell epitope would affect protective immunity to a previously encountered virus. Pichinde virus (PV) and lymphocytic choriomeningitis virus (LCMV) encode subdominant cross-reactive NP₂₀₅₋₂₁₂ CD8 T cell epitopes sharing 6 of 8 amino acids, differing only in the MHC anchoring regions. These pMHC epitopes induce cross-reactive but non-identical T cell receptor (TCR) repertoires, and structural studies showed that the differing anchoring amino acids altered the conformation of the MHC landscape presented to the TCR. PV-immune mice receiving an intervening infection with wild type but not NP205-mutant LCMV developed severe immunopathology in the form of acute fatty necrosis on re-challenge with PV, and this pathology could be predicted by the ratio of NP205-specific to the normally immunodominant PV NP₃₈₋₄₅-specific T cells. Thus, cross-reactive epitopes can exert pathogenic properties that compromise protective immunity by impairing more protective T cell responses.
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Affiliation(s)
- Alex T. Chen
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Markus Cornberg
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Stephanie Gras
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Carole Guillonneau
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Jamie Rossjohn
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Andrew Trees
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sebastien Emonet
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Juan C. de la Torre
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Raymond M. Welsh
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
| | - Liisa K. Selin
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
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205
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Chen AT, Cornberg M, Gras S, Guillonneau C, Rossjohn J, Trees A, Emonet S, de la Torre JC, Welsh RM, Selin LK. Loss of anti-viral immunity by infection with a virus encoding a cross-reactive pathogenic epitope. PLoS Pathog 2012; 8:e1002633. [PMID: 22536152 PMCID: PMC3334890 DOI: 10.1371/journal.ppat.1002633] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 02/23/2012] [Indexed: 12/31/2022] Open
Abstract
T cell cross-reactivity between different strains of the same virus, between different members of the same virus group, and even between unrelated viruses is a common occurrence. We questioned here how an intervening infection with a virus containing a sub-dominant cross-reactive T cell epitope would affect protective immunity to a previously encountered virus. Pichinde virus (PV) and lymphocytic choriomeningitis virus (LCMV) encode subdominant cross-reactive NP205–212 CD8 T cell epitopes sharing 6 of 8 amino acids, differing only in the MHC anchoring regions. These pMHC epitopes induce cross-reactive but non-identical T cell receptor (TCR) repertoires, and structural studies showed that the differing anchoring amino acids altered the conformation of the MHC landscape presented to the TCR. PV-immune mice receiving an intervening infection with wild type but not NP205-mutant LCMV developed severe immunopathology in the form of acute fatty necrosis on re-challenge with PV, and this pathology could be predicted by the ratio of NP205-specific to the normally immunodominant PV NP38–45 -specific T cells. Thus, cross-reactive epitopes can exert pathogenic properties that compromise protective immunity by impairing more protective T cell responses. The purpose of vaccination against viruses is to induce strong neutralizing antibody responses that inactivate viruses on contact and strong T cell responses that attack and kill virus-infected cells. Some viruses, however, like HIV and hepatitis C virus, are only weakly controlled by neutralizing antibody, so T cell immunity is very important for control of these infections. T cells recognize small virus-encoded peptides, called epitopes, presented on the surface of infected cells, and some of these epitopes induce strongly protective and others weakly protective T cell responses. However, the same T cells can sometimes demonstrate cross-reactivity and recognize similar epitopes encoded by two different viruses. We questioned here what infection with a virus encoding a weak cross-reactive epitope would do to immunity to a previously-encountered virus. Here we report that such an infection can compromise protective immunity by enhancing the normally weak response and suppressing the normally strong response. Under these conditions such epitopes function as “pathogenic” epitopes, and we suggest that the potential for inducing responses to pathogenic epitopes should be an important consideration in the design of T cell vaccines.
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Affiliation(s)
- Alex T. Chen
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Markus Cornberg
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Stephanie Gras
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Carole Guillonneau
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Jamie Rossjohn
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria, Australia
| | - Andrew Trees
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sebastien Emonet
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Juan C. de la Torre
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Raymond M. Welsh
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
| | - Liisa K. Selin
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
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206
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Calis JJA, de Boer RJ, Keşmir C. Degenerate T-cell recognition of peptides on MHC molecules creates large holes in the T-cell repertoire. PLoS Comput Biol 2012; 8:e1002412. [PMID: 22396638 PMCID: PMC3291541 DOI: 10.1371/journal.pcbi.1002412] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 01/18/2012] [Indexed: 11/18/2022] Open
Abstract
The cellular immune system screens peptides presented by host cells on MHC molecules to assess if the cells are infected. In this study we examined whether the presented peptides contain enough information for a proper self/nonself assessment by comparing the presented human (self) and bacterial or viral (nonself) peptides on a large number of MHC molecules. For all MHC molecules tested, only a small fraction of the presented nonself peptides from 174 species of bacteria and 1000 viral proteomes ([Formula: see text]0.2%) is shown to be identical to a presented self peptide. Next, we use available data on T-cell receptor-peptide-MHC interactions to estimate how well T-cells distinguish between similar peptides. The recognition of a peptide-MHC by the T-cell receptor is flexible, and as a result, about one-third of the presented nonself peptides is expected to be indistinguishable (by T-cells) from presented self peptides. This suggests that T-cells are expected to remain tolerant for a large fraction of the presented nonself peptides, which provides an explanation for the "holes in the T-cell repertoire" that are found for a large fraction of foreign epitopes. Additionally, this overlap with self increases the need for efficient self tolerance, as many self-similar nonself peptides could initiate an autoimmune response. Degenerate recognition of peptide-MHC-I complexes by T-cells thus creates large and potentially dangerous overlaps between self and nonself.
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Affiliation(s)
- Jorg J A Calis
- Theoretical Biology & Bioinformatics, Utrecht University, Utrecht, The Netherlands.
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207
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Brennan RM, Petersen J, Neller MA, Miles JJ, Burrows JM, Smith C, McCluskey J, Khanna R, Rossjohn J, Burrows SR. The Impact of a Large and Frequent Deletion in the Human TCR β Locus on Antiviral Immunity. THE JOURNAL OF IMMUNOLOGY 2012; 188:2742-8. [DOI: 10.4049/jimmunol.1102675] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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208
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Swain SL, McKinstry KK, Strutt TM. Expanding roles for CD4⁺ T cells in immunity to viruses. Nat Rev Immunol 2012; 12:136-48. [PMID: 22266691 PMCID: PMC3764486 DOI: 10.1038/nri3152] [Citation(s) in RCA: 601] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
CD4+ T cells are orchestrators, regulators and direct effectors of antiviral immunity. Neutralizing antibodies provide protection against many viral pathogens, and CD4+ T cells can help B cells to generate stronger and longer-lived antibody responses. CD4+ T cells help antiviral CD8+ T cells in two main ways: they maximize CD8+ T cell population expansion during a primary immune response and also facilitate the generation of virus-specific memory CD8+ T cell populations. In addition to their helper functions, CD4+ T cells contribute directly to viral clearance. They secrete cytokines with antiviral activities and, in some circumstances, can eliminate infected cells through cytotoxic killing. Memory CD4+ T cells provide superior protection during re-infection with a virus. Compared with new effector CD4+ T cells, memory CD4+ T cells have enhanced helper and effector functions and can rapidly trigger innate immune defence mechanisms early in the infection.
Immunity to viruses is typically associated with the development of cytotoxic CD8+ T cells. However, CD4+ T cells are also important for protection during viral infection. Here, the authors describe the various ways in which different CD4+T cell subsets can contribute to the antiviral immune response. Viral pathogens often induce strong effector CD4+ T cell responses that are best known for their ability to help B cell and CD8+ T cell responses. However, recent studies have uncovered additional roles for CD4+ T cells, some of which are independent of other lymphocytes, and have described previously unappreciated functions for memory CD4+ T cells in immunity to viruses. Here, we review the full range of antiviral functions of CD4+ T cells, discussing the activities of these cells in helping other lymphocytes and in inducing innate immune responses, as well as their direct antiviral roles. We suggest that all of these functions of CD4+ T cells are integrated to provide highly effective immune protection against viral pathogens.
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Affiliation(s)
- Susan L Swain
- Department of Pathology, University of Massachusetts Medical School, 55 Lake Avenue N, Worcester, Massachusetts 01655, USA.
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209
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Abstract
Nearly all human beings, by the time they reach adolescence, are infected with multiple herpesviruses. At any given time, this family of viruses accounts for 35-40 billion human infections worldwide, making herpesviruses among the most prevalent pathogens known to exist. Compared to most other viruses, herpesviruses are also unique in that infection lasts the life of the host. Remarkably, despite their prevalence and persistence, little is known about how these viruses interact with their hosts, especially during the clinically asymptomatic phase of infection referred to as latency. This review explores data in human and animal systems that reveal the ability of latent herpesviruses to modulate the immune response to self and environmental antigens. From the perspective of the host, there are both potentially detrimental and surprisingly beneficial effects of this lifelong interaction. The realization that latent herpesvirus infection modulates immune responses in asymptomatic hosts forces us to reconsider what constitutes a 'normal' immune system in a healthy individual.
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Affiliation(s)
- Douglas W. White
- Division of Rheumatology, Gundersen Lutheran Medical Center, La Crosse, WI, USA
| | - R. Suzanne Beard
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Department of Microbiology & Immunology, Wake Forest University School of Medicine, Winston-Salem NC, USA
| | - Erik S. Barton
- Department of Microbiology & Immunology, Wake Forest University School of Medicine, Winston-Salem NC, USA
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210
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Cross-reactivity and expansion of dengue-specific T cells during acute primary and secondary infections in humans. Sci Rep 2011; 1:51. [PMID: 22355570 PMCID: PMC3216538 DOI: 10.1038/srep00051] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 07/18/2011] [Indexed: 12/17/2022] Open
Abstract
Serotype-cross-reactive memory T cells responding to secondary dengue virus (DENV) infection are thought to contribute to disease. However, epitope-specific T cell responses have not been thoroughly compared between subjects with primary versus secondary DENV infection. We studied CD8(+) T cells specific for the HLA-A*1101-restricted NS3(133) epitope in a cohort of A11(+) DENV-infected patients throughout acute illness and convalescence. We compared the expansion, serotype-cross-reactivity, and activation of these cells in PBMC from patients experiencing primary or secondary infection and mild or severe disease by flow cytometry. Our results show expansion and activation of DENV-specific CD8(+) T cells during acute infection, which are predominantly serotype-cross-reactive regardless of DENV infection history. These data confirm marked T cell activation and serotype-cross-reactivity during the febrile phase of dengue; however, A11-NS3(133)-specific responses did not correlate with prior antigenic exposure or current disease severity.
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211
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Casadevall A, Fang FC, Pirofski LA. Microbial virulence as an emergent property: consequences and opportunities. PLoS Pathog 2011; 7:e1002136. [PMID: 21814511 PMCID: PMC3141035 DOI: 10.1371/journal.ppat.1002136] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Arturo Casadevall
- Department of Microbiology & Immunology and Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America.
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212
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Petrova GV, Naumova EN, Gorski J. The polyclonal CD8 T cell response to influenza M158-66 generates a fully connected network of cross-reactive clonotypes to structurally related peptides: a paradigm for memory repertoire coverage of novel epitopes or escape mutants. THE JOURNAL OF IMMUNOLOGY 2011; 186:6390-7. [PMID: 21518969 DOI: 10.4049/jimmunol.1004031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cross-reactivity of T cells is defined as recognition of two or more peptide-MHC complexes by the same T cell. Although examples of cross-reactivity have been reported, a detailed examination of cross-reactivity has not been performed. In this study, we took advantage of the high degree of polyclonality in the BV19 T cell repertoire responding to influenza M1(58-66) in HLA-A2 individuals to obtain a measure of simple cross-reactivity. We used substitutions that incrementally change the structure of the M1(58-66) peptide to measure how the HLA-A2-restricted response adapts to these changes. In three HLA-A2 adult subjects, we identified the BV19 clonotypes in the recall response to the influenza epitope M1(58-66) and 12 M1 peptides substituted at TCR contact position 63 or 65. The fraction of cross-reactive clonotypes in the M1(58-66) repertoire varied from 45-58% in the three donors. The extent of cross-reactivity, which is the additional number of peptides recognized by a single clonotype, is as high as six. We summarized the data using graph theory, with the cross-reactive clonotypes connecting the different HLA-A2 peptides recognized. The cross-reactive clonotypes form a well-connected network that could provide protection from virus-escape variants. We predict that any new pathogen with an epitope whose shape corresponds to that of the peptides that we studied would find a pre-existing repertoire ready to respond to it. We propose that in adult memory repertoires, previously encountered epitopes may have generated similar cross-reactive repertoires.
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Affiliation(s)
- Galina V Petrova
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI 53226, USA
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213
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van Eeden SF, Hogg JC. Chronic obstructive pulmonary disease: do regional differences in tissue inflammation matter? Respiration 2011; 81:359-61. [PMID: 21335946 DOI: 10.1159/000323869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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214
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Calcagno C, Puzone R, Pearson YE, Cheng Y, Ghersi D, Selin LK, Welsh RM, Celada F. Computer simulations of heterologous immunity: highlights of an interdisciplinary cooperation. Autoimmunity 2011; 44:304-14. [PMID: 21271821 DOI: 10.3109/08916934.2010.523220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The relationship between biological research and mathematical modeling is complex, critical, and vital. In this review, we summarize the results of the collaboration between two laboratories, exploring the interaction between mathematical modeling and wet-lab immunology. During this collaboration several aspects of the immune defence against viral infections were investigated, focusing primarily on the subject of heterologous immunity. In this manuscript, we emphasize the topics where computational simulations were applied in conjunction with experiments, such as immune attrition, the growing and shrinking of cross-reactive T cell repertoires following repeated infections, the short and long-term effects of cross-reactive immunological memory, and the factors influencing the appearance of new clonal specificities. For each topic, we describe how the mathematical model used was adapted to answer specific biological questions, and we discuss the hypotheses that were generated by simulations. Finally, we propose rules for testing hypotheses that emerge from model experimentation in the wet lab, and vice-versa.
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Affiliation(s)
- Claudia Calcagno
- Division of Rheumatology, Department of Medicine, New York University School of Medicine, New York, NY, USA
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215
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Selin LK, Wlodarczyk MF, Kraft AR, Nie S, Kenney LL, Puzone R, Celada F. Heterologous immunity: immunopathology, autoimmunity and protection during viral infections. Autoimmunity 2011; 44:328-47. [PMID: 21250837 DOI: 10.3109/08916934.2011.523277] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Heterologous immunity is a common phenomenon present in all infections. Most of the time it is beneficial, mediating protective immunity, but in some individuals that have the wrong crossreactive response it leads to a cascade of events that result in severe immunopathology. Infections have been associated with autoimmune diseases such as diabetes, multiple sclerosis and lupus erythematosis, but also with unusual autoimmune like pathologies where the immune system appears dysregulated, such as, sarcoidosis, colitis, panniculitis, bronchiolitis obliterans, infectious mononucleosis and even chronic fatigue syndrome. Here we review the evidence that to better understand these autoreactive pathologies it requires an evaluation of how T cells are regulated and evolve during sequential infections with different pathogens under the influence of heterologous immunity.
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Affiliation(s)
- Liisa K Selin
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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216
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Abstract
In wild populations, individuals are regularly exposed to a wide range of pathogens. In this context, organisms must elicit and regulate effective immune responses to protect their health while avoiding immunopathology. However, most of our knowledge about the function and dynamics of immune responses comes from laboratory studies performed on inbred mice in highly controlled environments with limited exposure to infection. Natural populations, on the other hand, exhibit wide genetic and environmental diversity. We argue that now is the time for immunology to be taken into the wild. The goal of 'wild immunology' is to link immune phenotype with host fitness in natural environments. To achieve this requires relevant measures of immune responsiveness that are both applicable to the host-parasite interaction under study and robustly associated with measures of host and parasite fitness. Bringing immunology to nonmodel organisms and linking that knowledge host fitness, and ultimately population dynamics, will face difficult challenges, both technical (lack of reagents and annotated genomes) and statistical (variation among individuals and populations). However, the affordability of new genomic technologies will help immunologists, ecologists and evolutionary biologists work together to translate and test our current knowledge of immune mechanisms in natural systems. From this approach, ecologists will gain new insight into mechanisms relevant to host health and fitness, while immunologists will be given a measure of the real-world health impacts of the immune factors they study. Thus, wild immunology can be the missing link between laboratory-based immunology and human, wildlife and domesticated animal health.
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Affiliation(s)
- Amy B Pedersen
- Centre for Immunity, Infection and Evolution, Institutes of Immunology & Infection Research and Evolutionary Biology, University of Edinburgh, Ashworth Labs, West Mains Road, Edinburgh EH9 3JT, UK.
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217
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Abstract
Vaccines work by eliciting an immune response and consequent immunological memory that mediates protection from infection or disease. Recently, new methods have been developed to dissect the immune response in experimental animals and humans, which have led to increased understanding of the molecular mechanisms that control differentiation and maintenance of memory T and B cells. In this review we will provide an overview of the cellular organization of immune memory and underline some of the outstanding questions on immunological memory and how they pertain to vaccination strategies. Finally we will discuss how we can learn about antigen design from the interrogation of our memory T and B cells-a journey from vaccines to memory and back.
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Affiliation(s)
- Federica Sallusto
- Institute for Research in Biomedicine, CH-6500 Bellinzona, Switzerland.
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218
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Abstract
Noroviruses are the principal cause of epidemic gastroenteritis worldwide. Multiple reports have concluded that the major capsid proteins of GII.4 strains, which cause 80% of norovirus infections worldwide, are evolving rapidly, resulting in new epidemic strains. Surrogate neutralization assays using sera from outbreaks and from immunized mice suggest that, as with influenza virus, antigenic variation maintains GII.4 persistence in the face of human population herd immunity. To test this hypothesis, mice were hyperimmunized with virus-like particles (VLPs) representing an early (GII.4-1987) and a contemporary (GII.4-2006) GII.4 strain. Anti-GII.4-1987 IgG monoclonal antibodies (MAbs) strongly reacted with GII.4 VLPs derived between only 1987 and 2002. Ligand binding blockade was more efficient with GII.4-1987 and GII.4-1997 VLPs than with GII.4-2002. Anti-GII.4-2006 IgG MAbs recognized either a broad panel of GII.4 VLPs (1987 to 2006) or a subset of contemporary (2004 to 2006) VLPs. Most 2006 antibodies did not recognize or only poorly recognized GII.4 VLPs of 2007 or 2008, documenting rapid antigenic evolution of GII.4 capsids. Generally, 2006 MAbs blocked homotypic VLP-ligand binding but were unable to block VLPs representing strains primarily circulating during or earlier than 2002. These analyses demonstrate that both subtle and significant evolutionary change has occurred within antibody epitopes between epidemic strains, providing direct evidence that the GII.4 noroviruses are undergoing antigenic variation, likely in response to herd immunity. As with influenza virus, HIV, and hepatitis C virus, norovirus antigenic variation will significantly influence the design of efficacious vaccines and immunotherapeutics against these important human pathogens.
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219
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Rouse BT, Lukacher AE. Some unmet challenges in the immunology of viral infections. DISCOVERY MEDICINE 2010; 10:363-370. [PMID: 21034678 PMCID: PMC3884557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Viral immunology is a rapidly evolving field. Major strides have been made in our understanding of innate and adaptive immune responses to viruses, largely based on highly reductionistic animal infection models, but more recently in humans, with validation that fundamental immunological concepts do in fact translate into clinical science well. From these studies there has emerged an appreciation of the enormous complexity of the immune response to viral infections as well as the diverse array of strategies developed by viruses to deal with immune detection. In this review, we highlight some of the major challenges we face in unraveling this complexity and summarize current efforts under way to improve the efficacy of viral vaccines.
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Affiliation(s)
- Barry T. Rouse
- Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, Tennessee 37996, USA.
| | - Aron E. Lukacher
- Department of Pathology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Lieberman J. Anatomy of a murder: how cytotoxic T cells and NK cells are activated, develop, and eliminate their targets. Immunol Rev 2010; 235:5-9. [PMID: 20536551 DOI: 10.1111/j.0105-2896.2010.00914.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Judy Lieberman
- Immune Disease Institute and Program in Cellular and Molecular Medicine, Children's Hospital Boston, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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