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Rojas M, Acosta-Ampudia Y, Heuer LS, Zang W, M Monsalve D, Ramírez-Santana C, Anaya JM, M Ridgway W, A Ansari A, Gershwin ME. Antigen-specific T cells and autoimmunity. J Autoimmun 2024; 148:103303. [PMID: 39141985 DOI: 10.1016/j.jaut.2024.103303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Revised: 07/31/2024] [Accepted: 08/05/2024] [Indexed: 08/16/2024]
Abstract
Autoimmune diseases (ADs) showcase the intricate balance between the immune system's protective functions and its potential for self-inflicted damage. These disorders arise from the immune system's erroneous targeting of the body's tissues, resulting in damage and disease. The ability of T cells to distinguish between self and non-self-antigens is pivotal to averting autoimmune reactions. Perturbations in this process contribute to AD development. Autoreactive T cells that elude thymic elimination are activated by mimics of self-antigens or are erroneously activated by self-antigens can trigger autoimmune responses. Various mechanisms, including molecular mimicry and bystander activation, contribute to AD initiation, with specific triggers and processes varying across the different ADs. In addition, the formation of neo-epitopes could also be implicated in the emergence of autoreactivity. The specificity of T cell responses centers on the antigen recognition sequences expressed by T cell receptors (TCRs), which recognize peptide fragments displayed by major histocompatibility complex (MHC) molecules. The assortment of TCR gene combinations yields a diverse array of T cell populations, each with distinct affinities for self and non-self antigens. However, new evidence challenges the traditional notion that clonal expansion solely steers the selection of higher-affinity T cells. Lower-affinity T cells also play a substantial role, prompting the "two-hit" hypothesis. High-affinity T cells incite initial responses, while their lower-affinity counterparts perpetuate autoimmunity. Precision treatments that target antigen-specific T cells hold promise for avoiding widespread immunosuppression. Nevertheless, detection of such antigen-specific T cells remains a challenge, and multiple technologies have been developed with different sensitivities while still harboring several drawbacks. In addition, elements such as human leukocyte antigen (HLA) haplotypes and validation through animal models are pivotal for advancing these strategies. In brief, this review delves into the intricate mechanisms contributing to ADs, accentuating the pivotal role(s) of antigen-specific T cells in steering immune responses and disease progression, as well as the novel strategies for the identification of antigen-specific cells and their possible future use in humans. Grasping the mechanisms behind ADs paves the way for targeted therapeutic interventions, potentially enhancing treatment choices while minimizing the risk of systemic immunosuppression.
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Affiliation(s)
- Manuel Rojas
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, CA, 95616, USA; Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia.
| | - Yeny Acosta-Ampudia
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
| | - Luke S Heuer
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, CA, 95616, USA
| | - Weici Zang
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, CA, 95616, USA
| | - Diana M Monsalve
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
| | - Carolina Ramírez-Santana
- Center for Autoimmune Diseases Research (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
| | | | - William M Ridgway
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, CA, 95616, USA
| | - Aftab A Ansari
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, CA, 95616, USA
| | - M Eric Gershwin
- Division of Rheumatology, Allergy and Clinical Immunology, University of California, Davis, CA, 95616, USA.
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Understanding the Role of HLA Class I Molecules in the Immune Response to Influenza Infection and Rational Design of a Peptide-Based Vaccine. Viruses 2022; 14:v14112578. [PMID: 36423187 PMCID: PMC9695287 DOI: 10.3390/v14112578] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 11/04/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
Influenza A virus is a respiratory pathogen that is responsible for regular epidemics and occasional pandemics that result in substantial damage to life and the economy. The yearly reformulation of trivalent or quadrivalent flu vaccines encompassing surface glycoproteins derived from the current circulating strains of the virus does not provide sufficient cross-protection against mismatched strains. Unlike the current vaccines that elicit a predominant humoral response, vaccines that induce CD8+ T cells have demonstrated a capacity to provide cross-protection against different influenza strains, including novel influenza viruses. Immunopeptidomics, the mass spectrometric identification of human-leukocyte-antigen (HLA)-bound peptides isolated from infected cells, has recently provided key insights into viral peptides that can serve as potential T cell epitopes. The critical elements required for a strong and long-living CD8+ T cell response are related to both HLA restriction and the immunogenicity of the viral peptide. This review examines the importance of HLA and the viral immunopeptidome for the design of a universal influenza T-cell-based vaccine.
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Broad-Based Influenza-Specific CD8 + T Cell Response without the Typical Immunodominance Hierarchy and Its Potential Implication. Viruses 2021; 13:v13061080. [PMID: 34198851 PMCID: PMC8229067 DOI: 10.3390/v13061080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/27/2021] [Accepted: 06/02/2021] [Indexed: 11/25/2022] Open
Abstract
Syngeneic murine systems have pre-fixed MHC, making them an imperfect model for investigating the impact of MHC polymorphism on immunodominance in influenza A virus (IAV) infections. To date, there are few studies focusing on MHC allelic differences and its impact on immunodominance even though it is well documented that an individual’s HLA plays a significant role in determining immunodominance hierarchy. Here, we describe a broad-based CD8+ T cell response in a healthy individual to IAV infection rather than a typical immunodominance hierarchy. We used a systematic antigen screen approach combined with epitope prediction to study such a broad CD8+ T cell response to IAV infection. We show CD8+ T cell responses to nine IAV proteins and identify their minimal epitope sequences. These epitopes are restricted to HLA-B*44:03, HLA-A*24:02 and HLA-A*33:03 and seven out of the nine epitopes are novel (NP319–330# (known and demonstrated minimal epitope positions are subscripted; otherwise, amino acid positions are shown as normal text (for example NP 319–330 or NP 313–330)), M1124–134, M27–15, NA337–346, PB239–49, HA445–453 and NS1195–203). Additionally, most of these novel epitopes are highly conserved among H1N1 and H3N2 strains that circulated in Australia and other parts of the world.
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Sng XYX, Li J, Zareie P, Assmus LM, Lee JKC, Jones CM, Turner SJ, Daley SR, Quinn KM, La Gruta NL. The Impact of MHC Class I Dose on Development and Maintenance of the Polyclonal Naive CD8+ T Cell Repertoire. THE JOURNAL OF IMMUNOLOGY 2020; 204:3108-3116. [DOI: 10.4049/jimmunol.2000081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/02/2020] [Indexed: 12/14/2022]
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Clemens EB, van de Sandt C, Wong SS, Wakim LM, Valkenburg SA. Harnessing the Power of T Cells: The Promising Hope for a Universal Influenza Vaccine. Vaccines (Basel) 2018; 6:vaccines6020018. [PMID: 29587436 PMCID: PMC6027237 DOI: 10.3390/vaccines6020018] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/21/2018] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Next-generation vaccines that utilize T cells could potentially overcome the limitations of current influenza vaccines that rely on antibodies to provide narrow subtype-specific protection and are prone to antigenic mismatch with circulating strains. Evidence from animal models shows that T cells can provide heterosubtypic protection and are crucial for immune control of influenza virus infections. This has provided hope for the design of a universal vaccine able to prime against diverse influenza virus strains and subtypes. However, multiple hurdles exist for the realisation of a universal T cell vaccine. Overall primary concerns are: extrapolating human clinical studies, seeding durable effective T cell resident memory (Trm), population human leucocyte antigen (HLA) coverage, and the potential for T cell-mediated immune escape. Further comprehensive human clinical data is needed during natural infection to validate the protective role T cells play during infection in the absence of antibodies. Furthermore, fundamental questions still exist regarding the site, longevity and duration, quantity, and phenotype of T cells needed for optimal protection. Standardised experimental methods, and eventually simplified commercial assays, to assess peripheral influenza-specific T cell responses are needed for larger-scale clinical studies of T cells as a correlate of protection against influenza infection. The design and implementation of a T cell-inducing vaccine will require a consensus on the level of protection acceptable in the community, which may not provide sterilizing immunity but could protect the individual from severe disease, reduce the length of infection, and potentially reduce transmission in the community. Therefore, increasing the standard of care potentially offered by T cell vaccines should be considered in the context of pandemic preparedness and zoonotic infections, and in combination with improved antibody vaccine targeting methods. Current pandemic vaccine preparedness measures and ongoing clinical trials under-utilise T cell-inducing vaccines, reflecting the myriad questions that remain about how, when, where, and which T cells are needed to fight influenza virus infection. This review aims to bring together basic fundamentals of T cell biology with human clinical data, which need to be considered for the implementation of a universal vaccine against influenza that harnesses the power of T cells.
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Affiliation(s)
- E Bridie Clemens
- Department of Microbiology and Immunology, The University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia.
| | - Carolien van de Sandt
- Department of Microbiology and Immunology, The University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia.
| | - Sook San Wong
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Linda M Wakim
- Department of Microbiology and Immunology, The University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia.
| | - Sophie A Valkenburg
- HKU Pasteur Research Pole, School of Public Health, University of Hong Kong, Hong Kong 999077, China.
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Tscharke DC, Croft NP, Doherty PC, La Gruta NL. Sizing up the key determinants of the CD8+ T cell response. Nat Rev Immunol 2015; 15:705-16. [DOI: 10.1038/nri3905] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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7
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Ni PP, Wang Y, Allen PM. Both positive and negative effects on immune responses by expression of a second class II MHC molecule. Mol Immunol 2014; 62:199-208. [PMID: 25016574 PMCID: PMC4157116 DOI: 10.1016/j.molimm.2014.06.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 12/24/2022]
Abstract
It is perplexing why vertebrates express a limited number of major histocompatibility complex (MHC) molecules when theoretically, having a greater repertoire of MHC molecules would increase the number of epitopes presented, thereby enhancing thymic selection and T cell response to pathogens. It is possible that any positive effects would either be neutralized or outweighed by negative selection restricting the T cell repertoire. We hypothesize that the limit on MHC number is due to negative consequences arising from expressing additional MHC. We compared T cell responses between B6 mice (I-A(+)) and B6.E(+) mice (I-A(+), I-E(+)), the latter expressing a second class II MHC molecule, I-E(b), due to a monomorphic Eα(k) transgene that pairs with the endogenous I-Eβ(b) chain. First, the naive T cell Vβ repertoire was altered in B6.E(+) thymi and spleens, potentially mediating different outcomes in T cell reactivity. Although the B6 and B6.E(+) responses to hen egg-white lysozyme (HEL) protein immunization remained similar, other immune models yielded differences. For viral infection, the quality of the T cell response was subtly altered, with diminished production of certain cytokines by B6.E(+) CD4(+) T cells. In alloreactivity, the B6.E(+) T cell response was significantly dampened. Finally, we observed markedly enhanced susceptibility to experimental autoimmune encephalomyelitis (EAE) in B6.E(+) mice. This correlated with decreased percentages of nTreg cells, supporting the concept of Tregs exhibiting differential susceptibility to negative selection. Altogether, our data suggest that expressing an additional class II MHC can produce diverse effects, with more severe autoimmunity providing a compelling explanation for limiting the expression of MHC molecules.
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Affiliation(s)
- Peggy P Ni
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid, Box 8118, St. Louis, MO 63110, United States
| | - Yaming Wang
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid, Box 8118, St. Louis, MO 63110, United States
| | - Paul M Allen
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid, Box 8118, St. Louis, MO 63110, United States.
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8
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Cukalac T, Chadderton J, Zeng W, Cullen JG, Kan WT, Doherty PC, Jackson DC, Turner SJ, La Gruta NL. The Influenza Virus–Specific CTL Immunodominance Hierarchy in Mice Is Determined by the Relative Frequency of High-Avidity T Cells. THE JOURNAL OF IMMUNOLOGY 2014; 192:4061-8. [DOI: 10.4049/jimmunol.1301403] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Akram A, Inman RD. Co-expression of HLA-B7 and HLA-B27 alleles is associated with B7-restricted immunodominant responses following influenza infection. Eur J Immunol 2013; 43:3254-67. [DOI: 10.1002/eji.201343597] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/11/2013] [Accepted: 09/23/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Ali Akram
- Division of Genetics and Development; Toronto Western Research Institute; Toronto Ontario Canada
- Department of Immunology; Faculty of Medicine; Institute of Medical Sciences; University of Toronto; Toronto Ontario Canada
| | - Robert D. Inman
- Department of Medicine; Faculty of Medicine; University of Toronto; Toronto Ontario Canada
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Hombrink P, Raz Y, Kester MGD, de Boer R, Weißbrich B, von dem Borne PA, Busch DH, Schumacher TNM, Falkenburg JHF, Heemskerk MHM. Mixed functional characteristics correlating with TCR-ligand koff -rate of MHC-tetramer reactive T cells within the naive T-cell repertoire. Eur J Immunol 2013; 43:3038-50. [PMID: 23893393 DOI: 10.1002/eji.201343397] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 06/05/2013] [Accepted: 07/23/2013] [Indexed: 11/10/2022]
Abstract
The low frequency of antigen-specific naïve T cells has challenged numerous laboratories to develop various techniques to study the naïve T-cell repertoire. Here, we combine the generation of naïve repertoire-derived antigen-specific T-cell lines based on MHC-tetramer staining and magnetic-bead enrichment with in-depth functional assessment of the isolated T cells. Cytomegalovirus (CMV) specific T-cell lines were generated from seronegative individuals. Generated T-cell lines consisted of a variety of immunodominant CMV-epitope-specific oligoclonal T-cell populations restricted to various HLA-molecules (HLA-A1, A2, B7, B8, and B40), and the functional and structural avidity of the CMV-specific T cells was studied. Although all CMV-specific T cells were isolated based on their reactivity toward a specific peptide-MHC complex, we observed a large variation in the functional avidity of the MHC-tetramer positive T-cell populations, which correlated with the structural avidity measured by the recently developed Streptamer koff -rate assay. Our data demonstrate that MHC-tetramer staining is not always predictive for specific T-cell reactivity, and challenge the sole use of MHC-tetramers as an indication of the peripheral T-cell repertoire, independent of the analysis of functional activity or structural avidity parameters.
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Affiliation(s)
- Pleun Hombrink
- Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands
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11
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Bacher P, Scheffold A. Flow-cytometric analysis of rare antigen-specific T cells. Cytometry A 2013; 83:692-701. [PMID: 23788442 DOI: 10.1002/cyto.a.22317] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 05/09/2013] [Accepted: 05/14/2013] [Indexed: 12/20/2022]
Abstract
The cytometric enumeration and characterization of antigen-specific lymphocytes, as introduced about 15 years ago, has contributed significantly to our understanding of adaptive immune responses in health and disease. Despite the development of several technologies, allowing to directly or indirectly analyze many aspects of lymphocyte specificity and function, several unresolved issues remain, due to the low frequency of certain antigen-specific lymphocyte subsets and the complexity of T cell antigen recognition. This is especially true for CD4(+) conventional as well as regulatory T cells, which bring major contributions to immune protection and pathology. Here we review the current technologies for the analysis of antigen specific T cells within the physiologic T cell repertoire and with a special focus on recent technologies addressing the analysis of rare antigen-specific T cell populations including naive and regulatory T cells.
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Affiliation(s)
- Petra Bacher
- Miltenyi Biotec GmbH, Bergisch Gladbach, Germany
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12
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Nayak JL, Sant AJ. Loss in CD4 T-cell responses to multiple epitopes in influenza due to expression of one additional MHC class II molecule in the host. Immunology 2012; 136:425-36. [PMID: 22747522 DOI: 10.1111/j.1365-2567.2012.03599.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
An understanding of factors controlling CD4 T-cell immunodominance is needed to pursue CD4 T-cell epitope-driven vaccine design, yet our understanding of this in humans is limited by the complexity of potential MHC class II molecule expression. In the studies described here, we took advantage of genetically restricted, well-defined mouse strains to better understand the effect of increasing MHC class II molecule diversity on the CD4 T-cell repertoire and the resulting anti-influenza immunodominance hierarchy. Interferon-γ ELISPOT assays were implemented to directly quantify CD4 T-cell responses to I-A(b) and I-A(s) restricted peptide epitopes following primary influenza virus infection in parental and F(1) hybrid strains. We found striking and asymmetric declines in the magnitude of many peptide-specific responses in F(1) animals. These declines could not be accounted for by the lower surface density of MHC class II on the cell or by antigen-presenting cells failing to stimulate T cells with lower avidity T-cell receptors. Given the large diversity of MHC class II expressed in humans, these findings have important implications for the rational design of peptide-based vaccines that are based on the premise that CD4 T-cell epitope specificity can be predicted by a simple cataloguing of an individual's MHC class II genotype.
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Affiliation(s)
- Jennifer L Nayak
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY 14642, USA.
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Ex vivo SIV-specific CD8 T cell responses in heterozygous animals are primarily directed against peptides presented by a single MHC haplotype. PLoS One 2012; 7:e43690. [PMID: 22928016 PMCID: PMC3425510 DOI: 10.1371/journal.pone.0043690] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 07/24/2012] [Indexed: 01/18/2023] Open
Abstract
The presence of certain MHC class I alleles is correlated with remarkable control of HIV and SIV, indicating that specific CD8 T cell responses can effectively reduce viral replication. It remains unclear whether epitopic breadth is an important feature of this control. Previous studies have suggested that individuals heterozygous at the MHC class I loci survive longer and/or progress more slowly than those who are homozygous at these loci, perhaps due to increased breadth of the CD8 T cell response. We used Mauritian cynomolgus macaques with defined MHC haplotypes and viral inhibition assays to directly compare CD8 T cell efficacy in MHC-heterozygous and homozygous individuals. Surprisingly, we found that cells from heterozygotes suppress viral replication most effectively on target cells from animals homozygous for only one of two potential haplotypes. The same heterozygous effector cells did not effectively inhibit viral replication as effectively on the target cells homozygous for the other haplotype. These results indicate that the greater potential breadth of CD8 T cell responses present in heterozygous animals does not necessarily lead to greater antiviral efficacy and suggest that SIV-specific CD8 T cell responses in heterozygous animals have a skewed focus toward epitopes restricted by a single haplotype.
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Jenkins MK, Moon JJ. The role of naive T cell precursor frequency and recruitment in dictating immune response magnitude. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 188:4135-40. [PMID: 22517866 PMCID: PMC3334329 DOI: 10.4049/jimmunol.1102661] [Citation(s) in RCA: 219] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent advances in technology have led to the realization that the populations of naive T cells specific for different foreign peptide:MHC (p:MHC) ligands vary in size. This variability is due, in part, to the fact that certain peptides contain amino acids that engage in particularly favorable interactions with TCRs. In addition, deletion of clones with cross-reactivity for self-p:MHC ligands may reduce the size of some naive populations. In many cases, the magnitude of the immune response to individual p:MHC epitopes correlates with the size of the corresponding naive populations. However, this simple relationship may be complicated by variability in the efficiency of T cell recruitment into the immune response. The knowledge that naive population size can predict immune response magnitude may create opportunities for production of more effective subunit vaccines.
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Affiliation(s)
- Marc K Jenkins
- Department of Microbiology, Center for Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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Horby P, Nguyen NY, Dunstan SJ, Baillie JK. The role of host genetics in susceptibility to influenza: a systematic review. PLoS One 2012; 7:e33180. [PMID: 22438897 PMCID: PMC3305291 DOI: 10.1371/journal.pone.0033180] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/06/2012] [Indexed: 12/24/2022] Open
Abstract
Background The World Health Organization has identified studies of the role of host genetics on susceptibility to severe influenza as a priority. A systematic review was conducted to summarize the current state of evidence on the role of host genetics in susceptibility to influenza (PROSPERO registration number: CRD42011001380). Methods and Findings PubMed, Web of Science, the Cochrane Library, and OpenSIGLE were searched using a pre-defined strategy for all entries up to the date of the search. Two reviewers independently screened the title and abstract of 1,371 unique articles, and 72 full text publications were selected for inclusion. Mouse models clearly demonstrate that host genetics plays a critical role in susceptibility to a range of human and avian influenza viruses. The Mx genes encoding interferon inducible proteins are the best studied but their relevance to susceptibility in humans is unknown. Although the MxA gene should be considered a candidate gene for further study in humans, over 100 other candidate genes have been proposed. There are however no data associating any of these candidate genes to susceptibility in humans, with the only published study in humans being under-powered. One genealogy study presents moderate evidence of a heritable component to the risk of influenza-associated death, and while the marked familial aggregation of H5N1 cases is suggestive of host genetic factors, this remains unproven. Conclusion The fundamental question “Is susceptibility to severe influenza in humans heritable?” remains unanswered. Not because of a lack of genotyping or analytic tools, nor because of insufficient severe influenza cases, but because of the absence of a coordinated effort to define and assemble cohorts of cases. The recent pandemic and the ongoing epizootic of H5N1 both represent rapidly closing windows of opportunity to increase understanding of the pathogenesis of severe influenza through multi-national host genetic studies.
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Affiliation(s)
- Peter Horby
- Oxford University Clinical Research Unit-Wellcome Trust Major Overseas Programme, Hanoi, Vietnam.
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Immunodominance: a pivotal principle in host response to viral infections. Clin Immunol 2012; 143:99-115. [PMID: 22391152 DOI: 10.1016/j.clim.2012.01.015] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 01/25/2012] [Accepted: 01/28/2012] [Indexed: 11/24/2022]
Abstract
We encounter pathogens on a daily basis and our immune system has evolved to mount an immune response following an infection. An interesting phenomenon that has evolved in response to clearing bacterial and viral infections is called immunodominance. Immunodominance refers to the phenomenon that, despite co-expression of multiple major histocompatibility complex class I alleles by host cells and the potential generation of hundreds of distinct antigenic peptides for recognition following an infection, a large portion of the anti-viral cytotoxic T lymphocyte population targets only some peptide/MHC class I complexes. Here we review the main factors contributing to immunodominance in relation to influenza A and HIV infection. Of special interest are the factors contributing to immunodominance in humans and rodents following influenza A infection. By critically reviewing these findings, we hope to improve understanding of the challenges facing the discovery of new factors enabling better anti-viral vaccine strategies in the future.
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