scholarly journals Self MHC class I–licensed NK cells enhance adaptive CD8 T-cell viral immunity

Blood ◽  
2011 ◽  
Vol 117 (19) ◽  
pp. 5133-5141 ◽  
Author(s):  
Michael D. Stadnisky ◽  
Xuefang Xie ◽  
Ebony R. Coats ◽  
Timothy N. Bullock ◽  
Michael G. Brown
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Mhc Class I ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Class I ◽  
Inhibitory Receptor ◽  
Class I Mhc ◽  
Mhc I

AbstractMHC class I (MHC I) is essential to NK- and T-cell effector and surveillance functions. However, it is unknown whether MHC I polymorphism influences adaptive immunity through NK cells. Previously, we found that MHC I Dk, a cognate ligand for the Ly49G2 inhibitory receptor, was essential to NK control of murine (M)CMV infection. Here we assessed the significance of NK inhibitory receptor recognition of MCMV on CD8 T cells in genetically defined MHC I Dk disparate mice. We observed that Dk-licensed Ly49G2+ NK cells stabilized and then enhanced conventional dendritic cells (cDCs) recovery after infection. Furthermore, licensed NK support of cDC recovery was essential to enhance the tempo, magnitude, and effector activity of virus-specific CD8 T cells. Minimal cDC and CD8 T-cell number differences after low-dose MCMV in Dk disparate animals further implied that licensed NK recognition of MCMV imparted qualitative cDC changes to enhance CD8 T-cell priming.

Platelet MHC Class I Mediates CD8+ T Cell Suppression During Sepsis

Blood ◽  
2021 ◽  
Author(s):  
Li Guo ◽  
Sikui Shen ◽  
Jesse W Rowley ◽  
Neal D. Tolley ◽  
Wenwen Jia ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Ex Vivo ◽  
Cd8 T Cell ◽  
Class I ◽  
Functional Responses ◽  
Class I Mhc ◽  
Mhc I

Circulating platelets interact with leukocytes to modulate host immune and thrombotic responses. In sepsis, platelet-leukocyte interactions are increased, and have been associated with adverse clinical events, including increased platelet-T cell interactions. Sepsis is associated with reduced CD8+ T cell numbers and functional responses, but whether platelets regulate CD8+ T cell responses during sepsis remains unknown. In our current study, we systemically evaluated platelet antigen internalization and presentation through major histocompatibility complex class I (MHC-I) and their effects on antigen specific CD8+ T cells in sepsis in vivo and ex vivo. We discovered that both human and murine platelets internalize and proteolyze exogenous antigens, generating peptides that are loaded onto MHC-I. The expression of platelet MHC-I, but not platelet MHC-II, is significantly increased in human and murine platelets during sepsis and in human megakaryocytes stimulated with agonists generated systemically during sepsis (e.g., IFN-g and LPS). Upregulation of platelet MHC-I during sepsis increases antigen cross-presentation and interactions with CD8+ T cells in an antigen-specific manner. Using a platelet lineage specific MHC-I deficient mouse strain (B2mf/f--Pf4Cre), we demonstrate that platelet MHC-I regulates antigen-specific CD8+ T cell proliferation in vitro, as well as the number and functional responses of CD8+ T cells in vivo during sepsis. Loss of platelet MHC-I reduced sepsis-associated mortality in mice in an antigen specific setting. These data identify a new mechanism by which platelets, through MHC-I, process and cross-present antigens, engage antigen specific CD8+ T cells, and regulate CD8+ T cell number, functional responses, and outcomes during sepsis.

scholarly journals TLR3 essentially promotes protective class I–restricted memory CD8+ T-cell responses to Aspergillus fumigatus in hematopoietic transplanted patients

Blood ◽  
2012 ◽  
Vol 119 (4) ◽  
pp. 967-977 ◽  
Author(s):  
Agostinho Carvalho ◽  
Antonella De Luca ◽  
Silvia Bozza ◽  
Cristina Cunha ◽  
Carmen D'Angelo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Aspergillus Fumigatus ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Class I ◽  
Class I Mhc ◽  
Cell Responses ◽  
Memory Cd8 T Cell

Abstract Aspergillus fumigatus is a model fungal pathogen and a common cause of severe infections and diseases. CD8+ T cells are present in the human and murine T-cell repertoire to the fungus. However, CD8+ T-cell function in infection and the molecular mechanisms that control their priming and differentiation into effector and memory cells in vivo remain elusive. In the present study, we report that both CD4+ and CD8+ T cells mediate protective memory responses to the fungus contingent on the nature of the fungal vaccine. Mechanistically, class I MHC-restricted, CD8+ memory T cells were activated through TLR3 sensing of fungal RNA by cross-presenting dendritic cells. Genetic deficiency of TLR3 was associated with susceptibility to aspergillosis and concomitant failure to activate memory-protective CD8+ T cells both in mice and in patients receiving stem-cell transplantations. Therefore, TLR3 essentially promotes antifungal memory CD8+ T-cell responses and its deficiency is a novel susceptibility factor for aspergillosis in high-risk patients.

scholarly journals Self–class I MHC molecules support survival of naive CD8 T cells, but depress their functional sensitivity through regulation of CD8 expression levels

2009 ◽  
Vol 206 (10) ◽  
pp. 2253-2269 ◽  
Author(s):  
Kensuke Takada ◽  
Stephen C. Jameson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Survival ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Class I ◽  
Class I Mhc ◽  
Mhc Molecules ◽  
T Cell Survival ◽  
And Function

Previous studies have suggested that naive CD8 T cells require self-peptide–major histocompatability complex (MHC) complexes for maintenance. However, interpretation of such studies is complicated because of the involvement of lymphopenic animals, as lymphopenia drastically alters naive T cell homeostasis and function. In this study, we explored naive CD8 T cell survival and function in nonlymphopenic conditions by using bone marrow chimeric donors and hosts in which class I MHC expression is absent or limited to radiosensitive versus radioresistant cells. We found that long-term survival of naive CD8 T cells (but not CD4 T cells) was impaired in the absence of class I MHC. However, distinct from this effect, class I MHC deprivation also enhanced naive CD8 T cell responsiveness to low-affinity (but not high-affinity) peptide–MHC ligands. We found that this improved sensitivity was a consequence of up-regulated CD8 levels, which was mediated through a transcriptional mechanism. Hence, our data suggest that, in a nonlymphopenic setting, self-class I MHC molecules support CD8 T cell survival, but that these interactions also attenuate naive T cell sensitivity by dynamic tuning of CD8 levels.

scholarly journals An antigen-specific pathway for CD8 T cells across the blood-brain barrier

2007 ◽  
Vol 204 (9) ◽  
pp. 2023-2030 ◽  
Author(s):  
Ian Galea ◽  
Martine Bernardes-Silva ◽  
Penny A. Forse ◽  
Nico van Rooijen ◽  
Roland S. Liblau ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class I ◽  
Blood Brain Barrier ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Class I ◽  
Cerebral Endothelium ◽  
Cognate Antigen ◽  
The Brain

CD8 T cells are nature's foremost defense in encephalitis and brain tumors. Antigen-specific CD8 T cells need to enter the brain to exert their beneficial effects. On the other hand, traffic of CD8 T cells specific for neural antigen may trigger autoimmune diseases like multiple sclerosis. T cell traffic into the central nervous system is thought to occur when activated T cells cross the blood-brain barrier (BBB) regardless of their antigen specificity, but studies have focused on CD4 T cells. Here, we show that selective traffic of antigen-specific CD8 T cells into the brain occurs in vivo and is dependent on luminal expression of major histocompatibility complex (MHC) class I by cerebral endothelium. After intracerebral antigen injection, using a minimally invasive technique, transgenic CD8 T cells only infiltrated the brain when and where their cognate antigen was present. This was independent of antigen presentation by perivascular macrophages. Marked reduction of antigen-specific CD8 T cell infiltration was observed after intravenous injection of blocking anti–MHC class I antibody. These results expose a hitherto unappreciated route by which CD8 T cells home onto their cognate antigen behind the BBB: luminal MHC class I antigen presentation by cerebral endothelium to circulating CD8 T cells. This has implications for a variety of diseases in which antigen-specific CD8 T cell traffic into the brain is a beneficial or deleterious feature.

scholarly journals The natural immune response to inhaled soluble protein antigens involves major histocompatibility complex (MHC) class I-restricted CD8+ T cell-mediated but MHC class II-restricted CD4+ T cell-dependent immune deviation resulting in selective suppression of immunoglobulin E production.

1993 ◽  
Vol 178 (3) ◽  
pp. 889-899 ◽  
Author(s):  
C McMenamin ◽  
P G Holt
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class I ◽  
Mhc Class Ii ◽  
Cd8 T Cells ◽  
Immunoglobulin E ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Class I

The immunological basis for atopy is currently ascribed to an inherent bias in the CD4+ T cell response to nonreplicating antigens presented at mucosal surfaces, resulting in dominance of the T helper 2 (Th2) interleukin 4 (IL-4)-producing phenotype, which favors IgE production. In contrast, the "normal" response to such antigens involves a predominance of interferon gamma (IFN-gamma)-producing Th1 clones. This difference has been suggested to be the result of active selection in atopics for Th2 (and hence against Th1) clones at the time of initial antigen presentation. In the study below, we demonstrate that the natural immune response to inhaled protein antigens, particularly in animals expressing the low immunoglobulin E (IgE) responder phenotype, includes a major histocompatibility complex (MHC) class I-restricted CD8+ T cell component, the appearance of which is associated with active suppression of IgE antibody production. Thus, continued exposure of rats to aerosolized ovalbumin (OVA) antigen elicits a transient IgE response, that is terminated by the onset of a state of apparent "tolerance" to further challenge, and this tolerant state is transferable to naive animals with CD8+ T cells. Kinetic studies on in vitro T cell reactivity in these aerosol-exposed rats demonstrated biphasic CD4+ Th2 responses which terminated, together with IgE antibody production, and coincident with the appearance of MHC class I-restricted OVA-specific IFN-gamma-producing CD8+ T cells. However, the latter were not autonomous in vitro and required a source of exogenous IL-2 for initial activation, which in CD(8+)-enriched splenocyte cultures could be provided by small numbers of contaminating OVA-specific CD4+ T cells. This represents the first formal evidence for the induction of an MHC class I-restricted T cell response to natural mucosal exposure to an inert protein antigen, and is consistent with a growing literature demonstrating sensitization of MHC class I-restricted CD8+ T cells by deliberate immunization with soluble proteins. We suggest that crossregulation of MHC class II-restricted CD4+ T cells via cytokine signals generated in parallel CD8+ T cell responses represents a covert and potentially important selection pressure that can shape the nature of host responses to nonreplicating antigens presented at mucosal surfaces.

scholarly journals CD8 T Cell Recognition of Endogenously Expressed Epstein-Barr Virus Nuclear Antigen 1

2004 ◽  
Vol 199 (10) ◽  
pp. 1409-1420 ◽  
Author(s):  
Steven P. Lee ◽  
Jill M. Brooks ◽  
Hatim Al-Jarrah ◽  
Wendy A. Thomas ◽  
Tracey A. Haigh ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class I ◽  
Cd8 T Cells ◽  
Epstein Barr Virus ◽  
Cd8 T Cell ◽  
Class I ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Epstein Barr

The Epstein-Barr virus (EBV) nuclear antigen (EBNA)1 contains a glycine-alanine repeat (GAr) domain that appears to protect the antigen from proteasomal breakdown and, as measured in cytotoxicity assays, from major histocompatibility complex (MHC) class I–restricted presentation to CD8+ T cells. This led to the concept of EBNA1 as an immunologically silent protein that although unique in being expressed in all EBV malignancies, could not be exploited as a CD8 target. Here, using CD8+ T cell clones to native EBNA1 epitopes upstream and downstream of the GAr domain and assaying recognition by interferon γ release, we show that the EBNA1 naturally expressed in EBV-transformed lymphoblastoid cell lines (LCLs) is in fact presented to CD8+ T cells via a proteasome/peptide transporter–dependent pathway. Furthermore, LCL recognition by such CD8+ T cells, although slightly lower than seen with paired lines expressing a GAr-deleted EBNA1 protein, leads to strong and specific inhibition of LCL outgrowth in vitro. Endogenously expressed EBNA1 is therefore accessible to the MHC class I pathway despite GAr-mediated stabilization of the mature protein. We infer that EBNA1-specific CD8+ T cells do play a role in control of EBV infection in vivo and might be exploitable in the control of EBV+ malignancies.

170 Microfluidics cell squeezing enables potent cellular vaccines in murine models through direct cytosolic loading and direct CD8 T cell priming

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A184-A184
Author(s):  
Emrah Ozay ◽  
Matthew Booty ◽  
Katarina Blagovic ◽  
David Soto ◽  
Olivia Pryor ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Median Survival ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
Cd8 T Cell ◽  
Laboratory Animals ◽  
Peripheral Blood Mononuclear ◽  
Class I Mhc ◽  
Mhc I

BackgroundThe presentation of sufficient antigen on major histocompatibility complex class I (MHC-I) is essential to prime CD8+ T cells.MethodsTo achieve efficient MHC-I presentation, we used microfluidics cell squeezing (Cell Squeeze®) to deliver antigens directly to the cytosol of antigen presenting cells (APCs), bypassing the need for cross-presentation. In addition to facilitating priming by professional APCs, this approach enables lymphocytic subsets within peripheral blood mononuclear cells (PBMCs) to function as unconventional APCs in mouse preclinical models.ResultsWe demonstrated that microfluidic cell squeezing delivers cargo to major cell populations within splenocytes (T cells, B cells, NK cells, and monocytes) and that protein, peptide, or mRNA antigens are rapidly processed and presented. In vivo, squeezed splenocytes directly presented antigen to CD8+ T cells. In the TC-1 tumor model for HPV+ cancers, squeezed splenocytes completely protect mice when administered prophylactically, protecting 15/15 animals from primary challenge and 11/15 animals from tumor re-challenge. Following therapeutic administration, squeezed splenocytes significantly improved median survival time to 56 days from 28 days, as observed with untreated controls. Immunization can also be combined with chemotherapy to further enhance therapeutic efficacy, improving median survival to over 100 days compared to 81 days with SQZ monotherapy or 32 days with chemotherapy alone. When tumor infiltrating lymphocytes (TILs) were analyzed following therapeutic immunization, squeezed splenocyte immunization elicited a significant influx of antigen specific CD8+ T cells: with SQZ treatment, ~87% of tumor-infiltrating CD8 T cells were antigen-specific, as measured by an E7-tetramer stain, while only ~33.6% and ~1.15% of infiltrating CD8 T cells were specific for E7 with subcutaneous peptide vaccination and no treatment, respectively.ConclusionsThrough the direct cytosolic delivery of antigen, we have engineered unfractionated PBMCs to function as potent APCs. This strategy generates potent antigen-specific CD8+ T cell responses in mouse models. Taken together, these findings support the potential of SQZ-PBMCs as an effective antigen-specific vaccination strategy against cancer. SQZ-PBMC-HPV is currently under clinical evaluation for HPV16+ tumor indications.Ethics ApprovalAll methods were performed in accordance with relevant guidelines and regulations; Animal studies were approved by the Institutional Animal Care and Use Committee (IACUC) at SQZ Biotechnologies, using the recommendations from the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health and the Office of Laboratory Animal Welfare. All activities were also conducted in accordance with Public Health Service (PHS) Policy on Humane Use and Care of Laboratory Animals.

scholarly journals Conditional silencing of H-2Dbclass I molecule expression on dendritic cells modulates the protective and pathogenic kinetics of virus-antigen specific CD8 T cell responses during Theiler’s Virus infection

2019 ◽  
Author(s):  
Zachariah P. Tritz ◽  
Robin C. Orozco ◽  
Courtney S. Malo ◽  
Lila T Yokanovich ◽  
Katayoun Ayasoufi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
Mhc Class I ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Class I ◽  
Viral Control ◽  
Cell Responses

ABSTRACTTheiler’s murine encephalomyelitis virus (TMEV) infection of the central nervous system is rapidly cleared in C57BL/6 mice by an anti-viral CD8 T cell response restricted by the MHC class I molecule, H-2Db. While the CD8 T cell response against neurotropic viruses is well characterized, the identity and function of the antigen presenting cell(s) involved in this process is(are) less well defined. To address this gap in knowledge, we developed a novel C57BL/6 H-2Dbconditional knockout mouse that expresses an H-2Dbtransgene in which the transmembrane domain locus is flanked by LoxP sites. We crossed these H-2DbLoxP mice with MHC class I-deficient mice expressing Cre-recombinase under either the CD11c or LysM promoter in order to silence H-2Dbrestricted antigen presentation predominantly in dendritic cells or macrophages, respectively. Upon challenge with intracranial TMEV infection, we observe that CD11c+ APCs are critical for early priming of CD8 T cells against the immunodominant TMEV peptide VP2121-130 presented in the context of the H-2Dbmolecule. This stands in stark contrast to later time points post TMEV infection where CD11c+ APCs appear dispensable for the activation of antigen-specific T cells; the functionality of these late-arising antiviral CD8 T cells is reflected in the restoration of viral control at later time points. These late-arising CD8 T cells also retain their capacity to induce blood-brain barrier disruption. In contrast, when H-2Dbrestricted antigen presentation was selectively silenced in LysM+ APCs there was no overt impact on the priming of Db:VP2121-130 epitope-specific CD8 T cells, although a modest reduction in immune cell entry into the CNS was observed. This work establishes a model system which enables critical dissection of MHC class I restricted antigen presentation to T cells, revealing cell specific and temporal features involved in the generation of antiviral CD8 T cell responses. Employing this novel system, we established CD11c+ cells as a pivotal driver of acute, but not later-arising, antiviral CD8 T cell responses against the TMEV immunodominant epitope VP2121-130, with functional implications both for T cell-mediated viral control and immunopathology.

Identification of Novel MHC Class I and Class II Epitopes of WT1 Using a Peptide Library Screen.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2764-2764 ◽  
Author(s):  
Katayoun Rezvani ◽  
Stephan Mielke ◽  
Yasemin Kilical ◽  
Matthias Grube ◽  
Hiroshi Fujiwara ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class I ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Class Ii ◽  
Peptide Library ◽  
Class I ◽  
Cell Responses

Abstract Although several HLA-A*0201-restricted immunodominant peptides from the leukemia-restricted protein WT-1 are characterized, T cell responses to peptide sequences binding to other common class I and II epitopes of WT-1 remain almost completely unexplored. A more comprehensive definition of the WT-1 antigen would extend peptide antigen vaccines to individuals lacking HLA-A*0201 and *2402 and improve vaccine potency by recruiting both CD4+ and CD8+ T cell responses. Here we used a WT1 peptide library to identify WT-1 peptide sequences inducing CD4+ and CD8+ T cell responses in normal individuals and patients with AML and other myeloid leukemias. Six cases were studied. The library consisted of 110 15mer peptides overlapping by 11aa covering the entire WT-1 protein in 21 pools. Monocytes were isolated by plastic adherence and pulsed with peptide pools for 3 hours. Autologous CD8+ and CD4+ T cells were then added. Pools of peptides were prepared in such a way that each peptide was represented in two different peptide pools, allowing the identification of the respective peptide by responses in the two corresponding pools. Cells were harvested for RNA extraction and reverse transcription. Real time PCR (RQ-PCR) was used to identify peptide-specific induction of IFN-γ and IL-2 in CD8+ and CD4+ T cells. The SYFPEITHI binding motif software was then used to predict the probable HLA restriction for the candidate epitopes. To confirm candidate peptide immunogenecity and HLA restriction, selected peptides were synthesized and tested individually. In addition to the known HLA-A*0201 peptides WT37, WT126, WT187 and WT235 we identified 20 new MHC class I and II epitopes of WT1. Four were restricted by more than one HLA allele, demonstrating the promiscuity of epitope binding. One epitope (VPGVAPTLV) was restricted to HLA-A*0201 and HLA-B*5101. One epitope (SGQFTGTAGACRYGP) was restricted by a class I HLA allele, namely HLA-*6801 and a class II HLA allele, DR*1501. Two epitopes (YGPFGPPPPSQASGQ and QKKFARSDELVRHHN) were restricted by multiple MHC class II alleles. The proliferative response of CD4+ and CD8+ T cells to candidate peptides was confirmed using CFSE labeling. We now plan to characterize the antileukemic effects of CD4+ and CD8+ T cells induced by these peptides with a view to designing broad-spectrum vaccines inducing leukemia-reactive T cells across a wide range of HLA types.

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