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Li Y, Aoki T, Iwabuchi S, Arai S, Iwabuchi N, Motobayashi H, Tanaka M, Hashimoto S. Immunomodulatory activity of heat-killed Lacticaseibacillus paracaseiMCC1849 based on the activation of plasmacytoid dendritic cells in the peripheral blood of healthy adults. Food Sci Nutr 2024; 12:3452-3460. [PMID: 38726445 PMCID: PMC11077237 DOI: 10.1002/fsn3.4009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 05/12/2024] Open
Abstract
Probiotics are widely used in food for their health benefits to the host. Inactivated probiotics also reportedly improve the intestinal environment and immune regulation. Our previous studies showed that heat-killed Lacticaseibacillus paracasei MCC1849 (hk-MCC1849) effectively induced IL-12 production in mouse spleen cells and significantly reduced cold symptoms in clinical trial subjects. To further elucidate the mechanism of host immune regulation by hk-MCC1849, human peripheral blood mononuclear cells (PBMCs) were cocultured with hk-MCC1849. The Toll-like receptor 9 ligands CpG-ODN 2216 and hk-MCC1849 and the heat-killed Lacticaseibacillus rhamnosus ATCC53103 were used as positive and negative controls, respectively. The results showed that, compared with the control, hk-MCC1849 significantly increased the expression of the plasmacytoid dendritic cell (pDC) marker CD86 (p < .0001) and the pDC marker HLA-DR (p < .001) in PBMCs. The expression levels of the IL-12p40, IFNα, IFNα1, IFNγ, and ISG15 genes were significantly increased after coculture with hk-MCC1849 (p < .05, p < .05, p < .05, p < .05, and p < .05, respectively, vs. control). Furthermore, to confirm whether hk-MCC1849 directly interacted with pDCs, DCs were enriched with PBMCs following 24 h of coculture with hk-MCC1849. Phagocytosis of fluorescently labeled hk-MCC1849 by pDCs was observed, and there were significant increases in CD86 (p < .05) and HLA-DR (p < .0001) expression in pDCs. These results suggest that hk-MCC1849 exerts a potential immunomodulatory effect on the host through the activation of peripheral pDCs.
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Affiliation(s)
- Yiran Li
- Innovative Research Institute, R&D Division, Morinaga Milk Industry Co., Ltd.ZamaKanagawaJapan
| | - Takahiro Aoki
- Innovative Research Institute, R&D Division, Morinaga Milk Industry Co., Ltd.ZamaKanagawaJapan
| | - Sadahiro Iwabuchi
- Department of Molecular PathophysiologyWakayama Medical UniversityWakayamaWakayamaJapan
| | - Satoshi Arai
- Innovative Research Institute, R&D Division, Morinaga Milk Industry Co., Ltd.ZamaKanagawaJapan
| | - Noriyuki Iwabuchi
- Innovative Research Institute, R&D Division, Morinaga Milk Industry Co., Ltd.ZamaKanagawaJapan
| | - Hideki Motobayashi
- Second Department of SurgeryWakayama Medical UniversityWakayamaWakayamaJapan
| | - Miyuki Tanaka
- Innovative Research Institute, R&D Division, Morinaga Milk Industry Co., Ltd.ZamaKanagawaJapan
| | - Shinichi Hashimoto
- Department of Molecular PathophysiologyWakayama Medical UniversityWakayamaWakayamaJapan
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2
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Innate and adaptive T cells in influenza disease. Front Med 2018; 12:34-47. [DOI: 10.1007/s11684-017-0606-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 10/24/2017] [Indexed: 12/25/2022]
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3
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Kennedy RB, Simon WL, Gibson MJ, Goergen KM, Grill DE, Oberg AL, Poland GA. The composition of immune cells serves as a predictor of adaptive immunity in a cohort of 50- to 74-year-old adults. Immunology 2016; 148:266-75. [PMID: 27188667 DOI: 10.1111/imm.12599] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/15/2016] [Accepted: 02/11/2016] [Indexed: 01/22/2023] Open
Abstract
Influenza causes significant morbidity and mortality annually. Although vaccination offers a considerable amount of protection, it is far from perfect, especially in aging populations. This is due to age-related defects in immune function, a process called immunosenescence. To date, there are no assays or methods to predict or explain variations in an individual's level of response to influenza vaccination. In this study, we measured levels of several immune cell subsets at baseline (Day 0) and at Days 3 and 28 post-vaccination using flow cytometry. Statistical modelling was performed to assess correlations between levels of cell subsets and Day 28 immune responses - haemagglutination inhibition (HAI) assay, virus neutralizing antibody (VNA) assay, and memory B cell ELISPOT. Changes in several groups of cell types from Day 0 to Day 28 and Day 3 to Day 28 were found to be significantly associated with immune response. Baseline levels of several immune cell subsets, including B cells and regulatory T cells, were able to partially explain variation in memory B-cell ELISPOT results. Increased expression of HLA-DR on plasmacytoid dendritic cells after vaccination was correlated with increased HAI and VNA responses. Our data suggest that the expression of activation markers (HLA-DR and CD86) on various immune cell subsets, as well as the relative distribution of cell subsets, both have value in predicting immune responses to influenza vaccination in older individuals.
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Affiliation(s)
| | | | | | - Krista M Goergen
- Division of Biomedical Statistics and Informatics, Department of Health Science Research, Mayo Clinic, Rochester, MN, USA
| | - Diane E Grill
- Division of Biomedical Statistics and Informatics, Department of Health Science Research, Mayo Clinic, Rochester, MN, USA
| | - Ann L Oberg
- Division of Biomedical Statistics and Informatics, Department of Health Science Research, Mayo Clinic, Rochester, MN, USA
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4
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Duan S, Thomas PG. Balancing Immune Protection and Immune Pathology by CD8(+) T-Cell Responses to Influenza Infection. Front Immunol 2016; 7:25. [PMID: 26904022 PMCID: PMC4742794 DOI: 10.3389/fimmu.2016.00025] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 01/18/2016] [Indexed: 02/05/2023] Open
Abstract
Influenza A virus (IAV) is a significant human pathogen causing annual epidemics and periodic pandemics. CD8+ cytotoxic T lymphocyte (CTL)-mediated immunity contributes to the clearance of virus-infected cells, and CTL immunity targeting the conserved internal proteins of IAVs is a key protection mechanism when neutralizing antibodies are absent during heterosubtypic IAV infection. However, CTL infiltration into the airways, its cytotoxicity, and the effects of produced proinflammatory cytokines can cause severe lung tissue injury, thereby contributing to immunopathology. Studies have discovered complicated and exquisite stimulatory and inhibitory mechanisms that regulate CTL magnitude and effector activities during IAV infection. Here, we review the state of knowledge on the roles of IAV-specific CTLs in immune protection and immunopathology during IAV infection in animal models, highlighting the key findings of various requirements and constraints regulating the balance of immune protection and pathology involved in CTL immunity. We also discuss the evidence of cross-reactive CTL immunity as a positive correlate of cross-subtype protection during secondary IAV infection in both animal and human studies. We argue that the effects of CTL immunity on protection and immunopathology depend on multiple layers of host and viral factors, including complex host mechanisms to regulate CTL magnitude and effector activity, the pathogenic nature of the IAV, the innate response milieu, and the host historical immune context of influenza infection. Future efforts are needed to further understand these key host and viral factors, especially to differentiate those that constrain optimally effective CTL antiviral immunity from those necessary to restrain CTL-mediated non-specific immunopathology in the various contexts of IAV infection, in order to develop better vaccination and therapeutic strategies for modifying protective CTL immunity.
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Affiliation(s)
- Susu Duan
- Department of Immunology, St. Jude Children's Research Hospital , Memphis, TN , USA
| | - Paul G Thomas
- Department of Immunology, St. Jude Children's Research Hospital , Memphis, TN , USA
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5
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Beyersdorf N, Kerkau T, Hünig T. CD28 co-stimulation in T-cell homeostasis: a recent perspective. Immunotargets Ther 2015; 4:111-22. [PMID: 27471717 PMCID: PMC4918251 DOI: 10.2147/itt.s61647] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
T-cells play a key role within the adaptive immune system mediating cellular immunity and orchestrating the immune response as a whole. Their activation requires not only recognition of antigen/major histocompatibility complexes by the T-cell receptor but in addition co-stimulation via the CD28 molecule through binding to CD80, CD86, or as recently discovered, inducible co-stimulator ligand expressed by antigen-presenting cells. Apart from tight control of the co-stimulatory signal by the T-cell receptor complex, expression of the inhibitory receptor cytotoxic T-lymphocyte antigen-4 (CTLA-4) sharing its ligands with CD28 is required to avoid inappropriate or prolonged T-cell activation. CD4(+) Foxp3(+) regulatory T (Treg) cells, which are crucial inhibitors of autoimmunity, add another level of complexity in that they differ from conventional non-regulatory CD4(+) T-cells by strongly depending on CD28 signaling for their generation and homeostasis. Moreover, CTLA-4 is constitutively expressed by Treg cells where it serves as a key mediator of suppression, while conventional CD4(+) T-cells express CTLA-4 only after activation. Here, we discuss recent insights into the molecular events underlying CD28-mediated co-stimulation, its impact on gene regulation, and the differential role of CD28 expression on Treg cells versus conventional CD4(+) and CD8(+) T-cells. Moreover, we summarize the exciting therapeutic options which have arisen from our current understanding of T-cell co-stimulation. Some of these have already been translated into the clinic, while others are expected to follow soon due to promising preclinical results. In particular, we discuss the failed 2006 trial of the CD28 superagonist TGN1412, and the return of this potent T-cell activator to clinical development.
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Affiliation(s)
- Niklas Beyersdorf
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Thomas Kerkau
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
| | - Thomas Hünig
- Institute for Virology and Immunobiology, University of Würzburg, Würzburg, Germany
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6
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Moser EK, Hufford MM, Braciale TJ. Late engagement of CD86 after influenza virus clearance promotes recovery in a FoxP3+ regulatory T cell dependent manner. PLoS Pathog 2014; 10:e1004315. [PMID: 25144228 PMCID: PMC4140856 DOI: 10.1371/journal.ppat.1004315] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 07/03/2014] [Indexed: 01/07/2023] Open
Abstract
Influenza A virus (IAV) infection in the respiratory tract triggers robust innate and adaptive immune responses, resulting in both virus clearance and lung inflammation and injury. After virus clearance, resolution of ongoing inflammation and tissue repair occur during a distinct recovery period. B7 family co-stimulatory molecules such as CD80 and CD86 have important roles in modulating T cell activity during the initiation and effector stages of the host response to IAV infection, but their potential role during recovery and resolution of inflammation is unknown. We found that antibody-mediated CD86 blockade in vivo after virus clearance led to a delay in recovery, characterized by increased numbers of lung neutrophils and inflammatory cytokines in airways and lung interstitium, but no change in conventional IAV-specific T cell responses. However, CD86 blockade led to decreased numbers of FoxP3+ regulatory T cells (Tregs), and adoptive transfer of Tregs into αCD86 treated mice rescued the effect of the blockade, supporting a role for Tregs in promoting recovery after virus clearance. Specific depletion of Tregs late after infection mimicked the CD86 blockade phenotype, confirming a role for Tregs during recovery after virus clearance. Furthermore, we identified neutrophils as a target of Treg suppression since neutrophil depletion in Treg-depleted mice reduced excess inflammatory cytokines in the airways. These results demonstrate that Tregs, in a CD86 dependent mechanism, contribute to the resolution of disease after IAV infection, in part by suppressing neutrophil-driven cytokine release into the airways.
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Affiliation(s)
- Emily K. Moser
- The Beirne B. Carter Center for Immunology Research, The University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pharmacology, The University of Virginia, Charlottesville, Virginia, United States of America
| | - Matthew M. Hufford
- The Beirne B. Carter Center for Immunology Research, The University of Virginia, Charlottesville, Virginia, United States of America
- Department of Microbiology, The University of Virginia, Charlottesville, Virginia, United States of America
| | - Thomas J. Braciale
- The Beirne B. Carter Center for Immunology Research, The University of Virginia, Charlottesville, Virginia, United States of America
- Department of Microbiology, The University of Virginia, Charlottesville, Virginia, United States of America
- Department of Pathology, The University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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7
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Strutt TM, McKinstry KK, Marshall NB, Vong AM, Dutton RW, Swain SL. Multipronged CD4(+) T-cell effector and memory responses cooperate to provide potent immunity against respiratory virus. Immunol Rev 2014; 255:149-64. [PMID: 23947353 DOI: 10.1111/imr.12088] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Over the last decade, the known spectrum of CD4(+) T-cell effector subsets has become much broader, and it has become clear that there are multiple dimensions by which subsets with a particular cytokine commitment can be further defined, including their stage of differentiation, their location, and, most importantly, their ability to carry out discrete functions. Here, we focus on our studies that highlight the synergy among discrete subsets, especially those defined by helper and cytotoxic function, in mediating viral protection, and on distinctions between CD4(+) T-cell effectors located in spleen, draining lymph node, and in tissue sites of infection. What emerges is a surprising multiplicity of CD4(+) T-cell functions that indicate a large arsenal of mechanisms by which CD4(+) T cells act to combat viruses.
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Affiliation(s)
- Tara M Strutt
- University of Massachusetts Medical School, Worcester, MA 01605, USA
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Ruckwardt TJ, Malloy AMW, Morabito KM, Graham BS. Quantitative and qualitative deficits in neonatal lung-migratory dendritic cells impact the generation of the CD8+ T cell response. PLoS Pathog 2014; 10:e1003934. [PMID: 24550729 PMCID: PMC3923758 DOI: 10.1371/journal.ppat.1003934] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/03/2014] [Indexed: 11/19/2022] Open
Abstract
CD103+ and CD11b+ populations of CD11c+MHCIIhi murine dendritic cells (DCs) have been shown to carry antigens from the lung through the afferent lymphatics to mediastinal lymph nodes (MLN). We compared the responses of these two DC populations in neonatal and adult mice following intranasal infection with respiratory syncytial virus. The response in neonates was dominated by functionally-limited CD103+ DCs, while CD11b+ DCs were diminished in both number and function compared to adults. Infecting mice at intervals through the first three weeks of life revealed an evolution in DC phenotype and function during early life. Using TCR transgenic T cells with two different specificities to measure the ability of CD103+ DC to induce epitope-specific CD8+ T cell responses, we found that neonatal CD103+ DCs stimulate proliferation in a pattern distinct from adult CD103+ DCs. Blocking CD28-mediated costimulatory signals during adult infection demonstrated that signals from this costimulatory pathway influence the hierarchy of the CD8+ T cell response to RSV, suggesting that limited costimulation provided by neonatal CD103+ DCs is one mechanism whereby neonates generate a distinct CD8+ T cell response from that of adults.
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Affiliation(s)
- Tracy J. Ruckwardt
- Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Allison M. W. Malloy
- Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kaitlyn M. Morabito
- Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Barney S. Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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9
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The transcription factor IRF4 is essential for TCR affinity-mediated metabolic programming and clonal expansion of T cells. Nat Immunol 2013; 14:1155-65. [PMID: 24056747 DOI: 10.1038/ni.2710] [Citation(s) in RCA: 301] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/13/2013] [Indexed: 12/12/2022]
Abstract
During immune responses, T cells are subject to clonal competition, which leads to the predominant expansion of high-affinity clones; however, there is little understanding of how this process is controlled. We found here that the transcription factor IRF4 was induced in a manner dependent on affinity for the T cell antigen receptor (TCR) and acted as a dose-dependent regulator of the metabolic function of activated T cells. IRF4 regulated the expression of key molecules required for the aerobic glycolysis of effector T cells and was essential for the clonal expansion and maintenance of effector function of antigen-specific CD8(+) T cells. Thus, IRF4 is an indispensable molecular 'rheostat' that 'translates' TCR affinity into the appropriate transcriptional programs that link metabolic function with the clonal selection and effector differentiation of T cells.
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10
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Nolte MA, van Lier RAW. With(out) a little help from my friends: an IL-12/CD40L-mediated feed-forward loop between CD8+ T cells and DCs. Eur J Immunol 2013; 43:1445-8. [PMID: 23661503 DOI: 10.1002/eji.201343644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 04/22/2013] [Accepted: 05/06/2013] [Indexed: 11/08/2022]
Abstract
CD40-CD40L interactions are important for both antigen-dependent B-cell differentiation and effector and memory T-cell formation. The prevailing view is that CD40L is expressed on activated CD4(+) T cells, which enables them to provide help to high-affinity B cells in GCs and to license DCs for efficient induction of CD8(+) T-cell responses. Interestingly, CD8(+) T cells themselves can also express CD40L and, in this issue of the European Journal of Immunology, Thiel and colleagues [Eur. J. Immunol. 2013. 43: 1511-1517] show that CD40L expression on these cells can be part of a self-sustaining feed-forward loop, in which expression of CD40L is induced by IL-12 and TCR signaling. This provides a paradigm shift in our thinking about the requirements of effector CD8(+) T-cell development and the role herein of CD4(+) T cells to provide help in this process.
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Affiliation(s)
- Martijn A Nolte
- Adaptive Immunity Lab, Department of Hematopoiesis, Sanquin Research and Landsteiner Laboratory AMC/UvA, Amsterdam, The Netherlands.
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11
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Clearance of influenza virus infections by T cells: risk of collateral damage? Curr Opin Virol 2013; 3:430-7. [PMID: 23721864 DOI: 10.1016/j.coviro.2013.05.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 04/24/2013] [Accepted: 05/01/2013] [Indexed: 02/02/2023]
Abstract
Influenza A viruses are a major cause of respiratory infections in humans. To protect against influenza, vaccines mainly aim at the induction of antibodies against the two surface proteins and do not protect against influenza A viruses from other subtypes. There is an increasing interest in heterosubtypic immunity that does protect against different subtypes. CD8 and CD4 T cells have a beneficial effect on the course of influenza A virus infection and can recognize conserved IAV epitopes. The T cell responses are tightly regulated to avoid collateral damage due to overreaction. Different studies have shown that an aberrant T cell response to an influenza virus infection could be harmful and could contribute to immunopathology. Here we discuss the recent findings on the balance between the beneficial and detrimental effects of T cell responses in influenza virus infections.
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12
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McKinstry KK, Dutton RW, Swain SL, Strutt TM. Memory CD4 T cell-mediated immunity against influenza A virus: more than a little helpful. Arch Immunol Ther Exp (Warsz) 2013; 61:341-53. [PMID: 23708562 DOI: 10.1007/s00005-013-0236-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 05/13/2013] [Indexed: 12/22/2022]
Abstract
Recent observations have uncovered multiple pathways whereby CD4 T cells can contribute to protective immune responses against microbial threats. Incorporating the generation of memory CD4 T cells into vaccine strategies thus presents an attractive approach toward improving immunity against several important human pathogens, especially those against which antibody responses alone are inadequate to confer long-term immunity. Here, we review how memory CD4 T cells provide protection against influenza viruses. We discuss the complexities of protective memory CD4 T cell responses observed in animal models and the potential challenges of translating these observations into the clinic. Specifically, we concentrate on how better understanding of organ-specific heterogeneity of responding cells and defining multiple correlates of protection might improve vaccine-generated memory CD4 T cells to better protect against seasonal, and more importantly, pandemic influenza.
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Affiliation(s)
- K Kai McKinstry
- Department of Pathology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA, 01583, USA,
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13
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Seah SGK, Brady JL, Carrington EM, Ng WC, Sutherland RM, Hancock MS, La Gruta NL, Brown LE, Turner SJ, Lew AM, Zhan Y. Influenza-induced, helper-independent CD8+ T cell responses use CD40 costimulation at the late phase of the primary response. J Leukoc Biol 2012; 93:145-54. [PMID: 23108101 DOI: 10.1189/jlb.0612266] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The helper-dependent pathway of priming CD8(+) T cells involves "licensing" of DCs by CD40L on CD4(+) T cells. The helper-independent ("helpless") pathways elicited by many viruses, including influenza, are less widely understood. We have postulated that CD40L can be up-regulated on DCs by such viruses, and this promotes priming of CD8(+) T cells via CD40. Most studies on costimulation have been performed in the presence of CD4(+) T cells, and so the role of CD40L costimulation under helpless circumstances has not been fully elucidated. Here, we investigated such a role for CD40L using CD40L KO mice. Although the number of influenza-specific CD8(+) T cells was unaffected by the absence of CD4(+) T cells, it was markedly decreased in the absence of CD40L. Proliferation (the number of CD44(+)BrdU(+) influenza-specific CD8(+) T cells) in the primary response was diminished in CD40L KO mice at Day 8 but not at Day 5 after infection. MLR studies indicated that CD40L expression on DCs was critical for CD8(+) T cell activation. Adoptive transfer of CD40 KO CD8(+) T cells compared with WT cells confirmed that CD40 on such cells was critical for the generation of primary anti-influenza CD8(+) T cell responses. The late effect also corresponded with the late expression of CD40 by influenza-specific CD8(+) T cells. We suggest that costimulation via CD40L on DCs and CD40 on CD8(+) T cells is important in optimizing primary CD8(+) T cell responses during influenza infection.
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Affiliation(s)
- Shirley G K Seah
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3052, Australia
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