scholarly journals Immune-checkpoint proteins VISTA and PD-1 nonredundantly regulate murine T-cell responses

2015 ◽  
Vol 112 (21) ◽  
pp. 6682-6687 ◽  
Author(s):  
Jun Liu ◽  
Ying Yuan ◽  
Wenna Chen ◽  
Juan Putra ◽  
Arief A. Suriawinata ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cell Receptor ◽  
T Cell Response ◽  
Cell Responses ◽  
Disease Penetrance ◽  
Immune Checkpoint Proteins

V-domain immunoglobulin suppressor of T-cell activation (VISTA) is a negative immune-checkpoint protein that suppresses T-cell responses. To determine whether VISTA synergizes with another immune-checkpoint, programmed death 1 (PD-1), this study characterizes the immune responses in VISTA-deficient, PD-1-deficient (KO) mice and VISTA/PD-1 double KO mice. Chronic inflammation and spontaneous activation of T cells were observed in both single KO mice, demonstrating their nonredundancy. However, the VISTA/PD-1 double KO mice exhibited significantly higher levels of these phenotypes than the single KO mice. When bred onto the 2D2 T-cell receptor transgenic mice, which are predisposed to development of inflammatory autoimmune disease in the CNS, the level of disease penetrance was significantly enhanced in the double KO mice compared with in the single KO mice. Consistently, the magnitude of T-cell response toward foreign antigens was synergistically higher in the VISTA/PD-1 double KO mice. A combinatorial blockade using monoclonal antibodies specific for VISTA and PD-L1 achieved optimal tumor-clearing therapeutic efficacy. In conclusion, our study demonstrates the nonredundant role of VISTA that is distinct from the PD-1/PD-L1 pathway in controlling T-cell activation. These findings provide the rationale to concurrently target VISTA and PD-1 pathways for treating T-cell-regulated diseases such as cancer.

scholarly journals Quantitative phosphoproteomic analysis reveals involvement of PD-1 in multiple T cell functions

2020 ◽  
Vol 295 (52) ◽  
pp. 18036-18050
Author(s):  
Anna S. Tocheva ◽  
Michael Peled ◽  
Marianne Strazza ◽  
Kieran R. Adam ◽  
Shalom Lerrer ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Synapse Formation ◽  
Significant Proportion ◽  
T Cell Responses ◽  
Protein Translation ◽  
Cell Receptor ◽  
Cell Functions ◽  
Cell Responses

Programmed cell death protein 1 (PD-1) is a critical inhibitory receptor that limits excessive T cell responses. Cancer cells have evolved to evade these immunoregulatory mechanisms by upregulating PD-1 ligands and preventing T cell–mediated anti-tumor responses. Consequently, therapeutic blockade of PD-1 enhances T cell–mediated anti-tumor immunity, but many patients do not respond and a significant proportion develop inflammatory toxicities. To improve anti-cancer therapy, it is critical to reveal the mechanisms by which PD-1 regulates T cell responses. We performed global quantitative phosphoproteomic interrogation of PD-1 signaling in T cells. By complementing our analysis with functional validation assays, we show that PD-1 targets tyrosine phosphosites that mediate proximal T cell receptor signaling, cytoskeletal organization, and immune synapse formation. PD-1 ligation also led to differential phosphorylation of serine and threonine sites within proteins regulating T cell activation, gene expression, and protein translation. In silico predictions revealed that kinase/substrate relationships engaged downstream of PD-1 ligation. These insights uncover the phosphoproteomic landscape of PD-1–triggered pathways and reveal novel PD-1 substrates that modulate diverse T cell functions and may serve as future therapeutic targets. These data are a useful resource in the design of future PD-1–targeting therapeutic approaches.

scholarly journals Induction of HLA-A2 restricted CD8 T cell responses against ApoB100 peptides does not affect atherosclerosis in a humanized mouse model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Frank H. Schaftenaar ◽  
Jacob Amersfoort ◽  
Hidde Douna ◽  
Mara J. Kröner ◽  
Amanda C. Foks ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Atherosclerotic Lesion ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
T Cell Epitopes ◽  
Mesenteric Lymph Nodes ◽  
Cell Responses

AbstractCardiovascular diseases form the most common cause of death worldwide, with atherosclerosis as main etiology. Atherosclerosis is marked by cholesterol rich lipoprotein deposition in the artery wall, evoking a pathogenic immune response. Characteristic for the disease is the pathogenic accumulation of macrophages in the atherosclerotic lesion, which become foam cells after ingestion of large quantities of lipoproteins. We hypothesized that, by inducing a CD8 T cell response towards lipoprotein derived apolipoprotein-B100 (ApoB100), lesional macrophages, that are likely to cross-present lipoprotein constituents, can specifically be eliminated. Based on in silico models for protein processing and MHC-I binding, 6 putative CD8 T cell epitopes derived from ApoB100 were synthesized. HLA-A2 binding was confirmed for all peptides by T2 cell binding assays and recall responses after vaccination with the peptides proved that 5 of 6 peptides could induce CD8 T cell responses. Induction of ApoB100 specific CD8 T cells did not impact plaque size and cellular composition in HLA-A2 and human ApoB100 transgenic LDLr−/− mice. No recall response could be detected in cultures of cells isolated from the aortic arch, which were observed in cell cultures of splenocytes and mesenteric lymph nodes, suggesting that the atherosclerotic environment impairs CD8 T cell activation.

scholarly journals L5 RIG-I activation enhances melanoma immunogenicity and improves anti-tumor T cell responses in combination with anti-PD-1 immune checkpoint blocking antibodies

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A3.1-A3
Author(s):  
B Thier ◽  
L Such ◽  
M Schwamborn ◽  
A Sucker ◽  
C Coch ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Immune Checkpoint ◽  
Cell Activation ◽  
T Cell Responses ◽  
Surface Expression ◽  
Melanoma Cells ◽  
Facs Analysis ◽  
Cell Responses

BackgroundClinical efficacy of immune checkpoint blocking (ICB) therapy critically relies on the killing of melanoma cells by CD8+ T cells, becoming activated upon recognition of tumor antigens presented by HLA class I (HLA-I) surface molecules. Patient-derived melanoma cells can escape from cytotoxic T cell effector functions by loss of HLA-I surface expression due to the silencing of HLA-I antigen processing and presentation machinery (APM) genes.Material and MethodsSeeking for a strategy to restore HLA-I expression, we transfected melanoma cells obtained from distinct patient metastasis with synthetic short double stranded RNA (3pRNA), an activating ligand of the cytosolic innate pattern recognition receptor RIG-I. 3pRNA-transfected melanoma cells were analyzed for HLA-I surface expression by FACS analysis and gene expression of HLA-I APM components by qPCR. In vivo 3pRNA-transfected tumors were analyzed for HLA-I expression by immunohistochemistry staining. Furthermore, T cell activation after coincubation with 3pRNA-transfected melanoma cells was determined by IFNγ-ELISpot assay. The effect of combined 3pRNA and blocking anti-PD-1 antibody treatment on T cell activation was measured by intracellular cytokine staining and FACS analysis.ResultsActivation of RIG-I by 3pRNA increased the expression of HLA-I APM components and strongly enhanced recognition of melanoma cells by autologous CD8+ T cells. Based on these findings, we asked whether the combination of 3pRNA and blocking anti-PD-1 antibodies could improve anti-melanoma T cell responses in an anti-PD-1 non-responder patient model. Indeed, T cell activation by 3pRNA-transfected melanoma cells was significantly increased in the presence of anti-PD-1 antibodies. In line with the enhancement of anti-tumor T cell responses, we found an association of elevated RIG-I mRNA levels with prolonged patient survival in TCGA melanoma samples.ConclusionsIn summary, this study demonstrates a beneficial effect of RIG-I activation on antigen presentation and T cell recognition of melanoma cells. Improved T cell responses by combined 3pRNA and anti-PD-1 treatment suggests that combinational therapy could be a strategy to overcome T cell resistance in melanoma.Disclosure InformationB. Thier: None. L. Such: None. M. Schwamborn: None. A. Sucker: None. C. Coch: None. D. Schadendorf: None. K. Griewank: None. M. Trilling: None. F. Zhao: None. A. Paschen: None.

scholarly journals Maintenance of Viral Suppression in Human Immunodeficiency Virus Controllers Despite Waning T-Cell Responses During Antiretroviral Therapy

2020 ◽  
Vol 222 (11) ◽  
pp. 1837-1842 ◽  
Author(s):  
Nikolaus Jilg ◽  
Pilar Garcia-Broncano ◽  
Michael Peluso ◽  
Florencia P Segal ◽  
Ronald J Bosch ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Undetectable Viremia ◽  
Hiv Controllers

Abstract AIDS Clinical Trials Group study A5308 found reduced T-cell activation and exhaustion in human immunodeficiency virus (HIV) controllers start antiretroviral therapy (ART). We further assessed HIV-specific T-cell responses and post-ART viral loads. Before ART, the 31% of participants with persistently undetectable viremia had more robust HIV-specific T-cell responses. During ART, significant decreases were observed in a broad range of T-cell responses. Eight controllers in A5308 and the Study of the Consequences of the Protease Inhibitor Era (SCOPE) cohort showed no viremia above the level of quantification in the first 12 weeks after ART discontinuation. ART significantly reduced HIV-specific T-cell responses in HIV controllers but did not adversely affect controller status after ART discontinuation.

scholarly journals Monkeypox virus evades antiviral CD4+ and CD8+ T cell responses by suppressing cognate T cell activation

2008 ◽  
Vol 105 (38) ◽  
pp. 14567-14572 ◽  
Author(s):  
E. Hammarlund ◽  
A. Dasgupta ◽  
C. Pinilla ◽  
P. Norori ◽  
K. Fruh ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Monkeypox Virus ◽  
Cell Responses

scholarly journals High Frequencies of Functional Virus-Specific CD4+ T Cells in SARS-CoV-2 Subjects With Olfactory and Taste Disorders

2021 ◽  
Vol 12 ◽  
Author(s):  
Dalila Mele ◽  
Anna Calastri ◽  
Eugenia Maiorano ◽  
Antonella Cerino ◽  
Michele Sachs ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Responses ◽  
Control Group ◽  
Presenting Symptoms ◽  
Cell Responses ◽  
Taste Disorders ◽  
Specific Igg

Olfactory and taste disorders (OTD) are commonly found as presenting symptoms of SARS-CoV-2 infection in patients with clinically mild COVID-19. Virus-specific T cells are thought to play an important role in the clearance of SARS-CoV-2; therefore the study of T cell specific immune responses in patients with mild symptoms may help to understand their possible role in protection from severe disease. We evaluated SARS-CoV-2-specific T cell responses to four different peptide megapools covering all SARS-CoV-2 proteins during the acute phase of the disease in 33 individuals with mild or no other symptom beside OTD and in 22 age-matched patients with severe infection. A control group of 15 outpatients with OTD and consistently negative nasopharyngeal SARS-CoV-2 RNA swabs and virus-specific IgG serology was included in the study. Increased frequencies of virus-specific CD4+ and CD8+ T cells were found in SARS-CoV-2 positive patients with OTD compared with those with severe COVID-19 and with SARS-CoV-2 negative OTD individuals. Moreover, enhanced CD4+ and CD8+ T-cell activation induced by SARS-CoV-2 peptides was associated with higher interferon (IFN)γ production. Increased frequencies of Spike (S1/S2)-specific CD4+ T cells showing enhanced IFNγ secretion and granzyme B content were associated with serum spike-specific IgG in the OTD group. In conclusion, patients with SARS-CoV-2 induced OTD develop highly functional virus-specific CD4+ and CD8+ T cells during the symptomatic phase of the disease, suggesting that robust and coordinated T-cell responses provide protection against extension of COVID-19 to the lower respiratory tract.

Abstract 449: Novel Role of Bim in the Regulation of Allogeneic T-Cell Activation and Development of Transplant Vasculopathy

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Anna von Rossum ◽  
Winnie Enns ◽  
Yu P Shi ◽  
Jonathan C Choy
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
T Cell Responses ◽  
Intimal Thickening ◽  
Cell Responses ◽  
Transplant Vasculopathy

Transplant vasculopathy (TV) is an arteriosclerotic disease characterized by intimal thickening of allograft arteries and is a leading cause of heart transplant rejection. T cell responses towards allograft arteries are responsible for the development of TV and understanding the regulatory pathways controlling T cell activation in allograft arteries provides opportunities for the therapeutic attenuation of TV as well as other arteriosclerotic diseases. Bim is a pro-apoptotic Bcl-2 protein known to down-regulate immune responses after viral infections by inducing cell death of effector T cells but its role in regulating allogeneic T cell responses is not known. We compared cell death and alloantigen-driven activation of T cells from Bim +/+ (wild-type), Bim +/- and Bim -/- mice as well as the development of TV in these mice. Bim was required for cell death of both CD4 and CD8 T cells in response to cytokine deprivation in vitro . Unexpectedly, Bim was also required for alloantigen-induced proliferation of both CD4 and CD8 T cells as well as for IL-2 production. When TV was examined in aortic interposition grafts implanted into complete major histocompatibility complex-mismatched mice, intimal thickening was significantly reduced in Bim +/- but not Bim -/- recipients as compared to Bim +/+ counterparts. There was signficantly less CD4 T cell accumulation in the intima of arteries from Bim +/- as compared to Bim +/+ recipients but this effect was not observed in Bim -/- recipients. The accumulation of CD8 T cells in allograft arteries was not affected by differences in Bim expression. Taken together, our data support a novel role for Bim in driving T cell activation in response to allogeneic stimuli and indicate that the effects of this Bcl-2 protein in the pathogenesis of TV likely depends on its dual role in supporting T cell activation and death.

scholarly journals Vector Order Determines Protection against Pathogenic Simian Immunodeficiency Virus Infection in a Triple-Component Vaccine by Balancing CD4+ and CD8+ T-Cell Responses

2017 ◽  
Vol 91 (23) ◽  
Author(s):  
Ulrike Sauermann ◽  
Antonia Radaelli ◽  
Nicole Stolte-Leeb ◽  
Katharina Raue ◽  
Massimiliano Bissa ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Responses ◽  
Target Cells ◽  
Aids Vaccine ◽  
Cell Responses ◽  
Antibody Titers

ABSTRACT An effective AIDS vaccine should elicit strong humoral and cellular immune responses while maintaining low levels of CD4+ T-cell activation to avoid the generation of target cells for viral infection. The present study investigated two prime-boost regimens, both starting vaccination with single-cycle immunodeficiency virus, followed by two mucosal boosts with either recombinant adenovirus (rAd) or fowlpox virus (rFWPV) expressing SIVmac239 or SIVmac251 gag/pol and env genes, respectively. Finally, vectors were switched and systemically administered to the reciprocal group of animals. Only mucosal rFWPV immunizations followed by systemic rAd boost significantly protected animals against a repeated low-dose intrarectal challenge with pathogenic SIVmac251, resulting in a vaccine efficacy (i.e., risk reduction per exposure) of 68%. Delayed viral acquisition was associated with higher levels of activated CD8+ T cells and Gag-specific gamma interferon (IFN-γ)-secreting CD8+ cells, low virus-specific CD4+ T-cell responses, and low Env antibody titers. In contrast, the systemic rFWPV boost induced strong virus-specific CD4+ T-cell activity. rAd and rFWPV also induced differential patterns of the innate immune responses, thereby possibly shaping the specific immunity. Plasma CXCL10 levels after final immunization correlated directly with virus-specific CD4+ T-cell responses and inversely with the number of exposures to infection. Also, the percentage of activated CD69+ CD8+ T cells correlated with the number of exposures to infection. Differential stimulation of the immune response likely provided the basis for the diverging levels of protection afforded by the vaccine regimen. IMPORTANCE A failed phase II AIDS vaccine trial led to the hypothesis that CD4+ T-cell activation can abrogate any potentially protective effects delivered by vaccination or promote acquisition of the virus because CD4+ T helper cells, required for an effective immune response, also represent the target cells for viral infection. We compared two vaccination protocols that elicited similar levels of Gag-specific immune responses in rhesus macaques. Only the animal group that had a low level of virus-specific CD4+ T cells in combination with high levels of activated CD8+ T cells was significantly protected from infection. Notably, protection was achieved despite the lack of appreciable Env antibody titers. Moreover, we show that both the vector and the route of immunization affected the level of CD4+ T-cell responses. Thus, mucosal immunization with FWPV-based vaccines should be considered a potent prime in prime-boost vaccination protocols.

scholarly journals Specific interaction of lymphocyte function-associated antigen 3 with CD2 can inhibit T cell responses.

1993 ◽  
Vol 178 (1) ◽  
pp. 211-222 ◽  
Author(s):  
G T Miller ◽  
P S Hochman ◽  
W Meier ◽  
R Tizard ◽  
S A Bixler ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
T Cell Activation ◽  
Cell Activation ◽  
Hepatitis B Surface Antigen ◽  
Specific Interaction ◽  
T Cell Responses ◽  
Accessory Cell ◽  
Lymphocyte Function ◽  
Cell Responses

Accessory cell surface molecules, such as T cell antigen CD2 and its ligand lymphocyte function-associated antigen 3 (LFA-3; CD58), are critical costimulatory pathways for optimal T cell activation in response to antigens. Interaction of CD2 with cell surface LFA-3 not only increases T cell/accessory cell adhesion, but also induces signal transduction events involved in the regulation of T cell responses. In this report, we show that specific interactions of LFA-3 with CD2 can result in T cell unresponsiveness to antigenic or mitogenic stimuli in vitro. By deletion of certain regions of the extracellular domain of LFA-3, we localized the CD2 binding site to the first domain of LFA-3. We then demonstrated that a soluble, purified first domain-LFA-3/IgG1 fusion protein (LFA3TIP) interacts with CD2 and binds to the same CD2 epitope as purified multimeric or cell surface-expressed LFA-3. LFA3TIP inhibits tetanus toxoid, hepatitis B surface antigen, anti-CD3 mAb, Con A, and phytohemagglutinin P-induced T cell proliferation, as well as xenogeneic and allogeneic mixed lymphocyte reactions (MLR). Unlike anti-LFA-3 or anti-CD2 monoclonal antibodies (mAbs) which inhibit T cell responses by blocking LFA-3/CD2 binding, LFA3TIP is capable of rendering T cells unresponsive to antigenic stimuli in situations where T cell activation is independent of CD2/LFA-3 interactions. Furthermore, LFA3TIP, but not blocking anti-CD2 mAbs, is capable of inducing T cell unresponsiveness to secondary stimulation in allogeneic MLR. This inhibition of T cell responses by LFA3TIP occurs through a different mechanism from that of mAbs to LFA-3 or CD2.

scholarly journals Virus-based vaccine vectors with distinct replication mechanisms differentially infect and activate dendritic cells

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Carolina Chiale ◽  
Anthony M. Marchese ◽  
Yoichi Furuya ◽  
Michael D. Robek
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Virus Replication ◽  
T Cell Activation ◽  
Viral Vectors ◽  
Cell Activation ◽  
T Cell Responses ◽  
Cell Responses ◽  
Identical Cell

AbstractThe precise mechanism by which many virus-based vectors activate immune responses remains unknown. Dendritic cells (DCs) play key roles in priming T cell responses and controlling virus replication, but their functions in generating protective immunity following vaccination with viral vectors are not always well understood. We hypothesized that highly immunogenic viral vectors with identical cell entry pathways but unique replication mechanisms differentially infect and activate DCs to promote antigen presentation and activation of distinctive antigen-specific T cell responses. To evaluate differences in replication mechanisms, we utilized a rhabdovirus vector (vesicular stomatitis virus; VSV) and an alphavirus-rhabdovirus hybrid vector (virus-like vesicles; VLV), which replicates like an alphavirus but enters the cell via the VSV glycoprotein. We found that while virus replication promotes CD8+ T cell activation by VLV, replication is absolutely required for VSV-induced responses. DC subtypes were differentially infected in vitro with VSV and VLV, and displayed differences in activation following infection that were dependent on vector replication but were independent of interferon receptor signaling. Additionally, the ability of the alphavirus-based vector to generate functional CD8+ T cells in the absence of replication relied on cDC1 cells. These results highlight the differential activation of DCs following infection with unique viral vectors and indicate potentially discrete roles of DC subtypes in activating the immune response following immunization with vectors that have distinct replication mechanisms.

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