scholarly journals Direct Priming of CD8+ T Cells Persists in the Face of Cowpox Virus Inhibitors of Antigen Presentation

2021 ◽  
Author(s):  
Leon C.W. Lin ◽  
Sarah N. Croft ◽  
Nathan P. Croft ◽  
Yik Chun Wong ◽  
Stewart A. Smith ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
T Cell Responses ◽  
Cowpox Virus ◽  
Viral Immunity ◽  
Cell Responses ◽  
Infected Cells ◽  
The Impact ◽  
Viral Inhibitors

Vaccinia virus (VACV) was the vaccine used to eradicate smallpox and is being repurposed as a vaccine vector. CD8+ T cells are key anti-viral mediators, but require priming to become effector or memory cells. Priming requires an interaction with dendritic cells that are either infected (direct priming), or that have acquired virus proteins but remain uninfected (cross priming). To investigate CD8+ T cell priming pathways for VACV, we engineered the virus to express CPXV12 and CPXV203, two inhibitors of antigen presentation encoded by cowpox virus. These intracellular proteins would be expected to block direct but not cross priming. The inhibitors had diverse impacts on the size of anti-VACV CD8+ T cell responses across epitopes and by different infection routes in mice, superficially suggesting variable use of direct and cross priming. However, when we then tested a form of antigen that requires direct priming, we found surprisingly that CD8+ T cell responses were not diminished by co-expression with CPXV12 and CPXV203. We then directly quantified the impact of CPXV12 and CPXV203 on viral antigen presentation using mass spectrometry, which revealed strong, but incomplete inhibition of antigen presentation by the CPXV proteins. Therefore, direct priming of CD8+ T cells by poxviruses is robust enough to withstand highly potent viral inhibitors of antigen presentation. This is a reminder of the limits of viral immune evasion and shows that viral inhibitors of antigen presentation cannot be assumed to dissect cleanly direct and cross priming of anti-viral CD8+ T cells. Importance CD8+ T cells are key to anti-viral immunity, so it is important to understand how they are activated. Many viruses have proteins that protect infected cells from T cell attack by interfering with the process that allows virus infection to be recognised by CD8+ T cells. It is thought that these proteins would also stop infected cells from activating T cells in the first place. However, we show here that this is not the case for two very powerful inhibitory proteins from cowpox virus. This demonstrates the flexibility and robustness of immune processes that turn on the immune responses required to fight infection.

scholarly journals Batf3-Dependent Dendritic Cells Promote Optimal CD8 T Cell Responses against Respiratory Poxvirus Infection

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Pritesh Desai ◽  
Vikas Tahiliani ◽  
Georges Abboud ◽  
Jessica Stanfield ◽  
Shahram Salek-Ardakani
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Vaccinia Virus ◽  
Respiratory Infection ◽  
Host Resistance ◽  
T Cell Responses ◽  
Cell Responses ◽  
Ifn Γ ◽  
The Impact

ABSTRACTRespiratory infection with vaccinia virus (VacV) elicits robust CD8+T cell responses that play an important role in host resistance. In the lung, VacV encounters multiple tissue-resident antigen-presenting cell (APC) populations, but which cell plays a dominant role in priming of virus-specific CD8+effector T cell responses remains poorly defined. We used Batf3−/−mice to investigate the impact of CD103+and CD8α+dendritic cell (DC) deficiency on anti-VacV CD8+T cell responses. We found that Batf3−/−mice were more susceptible to VacV infection, exhibiting profound weight loss, which correlated with impaired accumulation of gamma interferon (IFN-γ)-producing CD8+T cells in the lungs. This was largely due to defective priming since early in the response, antigen-specific CD8+T cells in the draining lymph nodes of Batf3−/−mice expressed significantly reduced levels of Ki67, CD25, and T-bet. These results underscore a specific role for Batf3-dependent DCs in regulating priming and expansion of effector CD8+T cells necessary for host resistance against acute respiratory VacV infection.IMPORTANCEDuring respiratory infection with vaccinia virus (VacV), a member ofPoxviridaefamily, CD8+T cells play important role in resolving the primary infection. Effector CD8+T cells clear the virus by accumulating in the infected lungs in large numbers and secreting molecules such as IFN-γ that kill virally infected cells. However, precise cell types that regulate the generation of effector CD8+T cells in the lungs are not well defined. Dendritic cells (DCs) are a heterogeneous population of immune cells that are recognized as key initiators and regulators of T-cell-mediated immunity. In this study, we reveal that a specific subset of DCs that are dependent on the transcription factor Batf3 for their development regulate the magnitude of CD8+T cell effector responses in the lungs, thereby providing protection during pulmonary VacV infection.

scholarly journals Regulation of T Cell Responses by Ionic Salt Signals

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2365
Author(s):  
Christina E. Zielinski
Keyword(s):  
T Cells ◽  
T Cell ◽  
Sodium Chloride ◽  
T Cell Responses ◽  
T Helper Cell ◽  
Helper Cell ◽  
T Helper ◽  
Tissue Microenvironment ◽  
Cell Responses ◽  
The Impact

T helper cell responses are tailored to their respective antigens and adapted to their specific tissue microenvironment. While a great proportion of T cells acquire a resident identity, a significant proportion of T cells continue circulating, thus encountering changing microenvironmental signals during immune surveillance. One signal, which has previously been largely overlooked, is sodium chloride. It has been proposed to have potent effects on T cell responses in the context of autoimmune, allergic and infectious tissue inflammation in mouse models and humans. Sodium chloride is stringently regulated in the blood by the kidneys but displays differential deposition patterns in peripheral tissues. Sodium chloride accumulation might furthermore be regulated by dietary intake and thus by intentional behavior. Together, these results make sodium chloride an interesting but still controversial signal for immune modulation. Its downstream cellular activities represent a potential therapeutic target given its effects on T cell cytokine production. In this review article, we provide an overview and critical evaluation of the impact of this ionic signal on T helper cell polarization and T helper cell effector functions. In addition, the impact of sodium chloride from the tissue microenvironment is assessed for human health and disease and for its therapeutic potential.

scholarly journals Vaccinia-specific cytotoxic T-cell responses in the context of H-2 antigens not encountered in thymus may reflect aberrant recognition of a virus-H-2 complex.

1979 ◽  
Vol 149 (1) ◽  
pp. 150-157 ◽  
Author(s):  
P C Doherty ◽  
J C Bennink
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vaccinia Virus ◽  
T Cell Responses ◽  
Cytotoxic T Cell ◽  
Cell Responses ◽  
Antigen Complex ◽  
Infected Cells ◽  
Cytotoxic T Cell Responses

BALB/c (H-2Kd-Dd) spleen and lymph node populations were specifically depleted of alloreactive potential by filtration through H-2 different, irradiated recipients. These negatively selected T cells were then stimulated with vaccinia virus in mice expressing the foreign H-2 determinants encountered previously in the filter environment. Strong virus-immune cytotoxic T-cell responses were seen in the context of H-2Kk and H-2Ks, but not 2H-2Kb. The T cells generated were not cross-reactive for the H-2Kk and H-2Kd alleles, and responsiveness was independent of concurrent presence of effector populations operating at H-2D. These findings are consisent with the idea that recognition is mediated via a complex receptor, part of which is specific for virus and part for self H-2. The capacity to interact with allogeneic, virus-infected cells may then reflect aberrant recognition of a virus-H-2-antigen complex by this single, large binding site. For instance, the T cell which would normally recognize H-2Kd-virus x, or H-2Dd-minor histocompatibility antigen Z, may now show specificity for H-2Kk-vaccinia virus. Implications for both the selective role of the thymus and for mechanisms of tolerance are discussed.

Obesity results in higher PD-1-mediated T-cell suppression but greater T-cell effector functions following blockade.

2018 ◽  
Vol 36 (5_suppl) ◽  
pp. 65-65 ◽  
Author(s):  
Robert J. Canter ◽  
Ethan Aguilar ◽  
Ziming Wang ◽  
Catherine Le ◽  
Lam Khuat ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Responses ◽  
Murine Cytomegalovirus ◽  
Obese Mice ◽  
Effector Functions ◽  
Cell Responses ◽  
The Central Nervous System ◽  
The Impact ◽  
Cell Effector

65 Background: Obesity is increasingly prevalent and viewed as a critical co-factor in many pathologic conditions due to metabolic, inflammatory and immune perturbations. We performed a multi-species evaluation of the impact of obesity T cell effector functions and markers of immune exhaustion. Methods: We examined the impact of obesity on PD-1 and T cell-mediated responses across different pre-clinical models (tumor, infection, and autoimmune encephalomyelitis [EAE]) and species (mouse, dog, non-human primate, and human). Results: CD4 and CD8 T cells from obese mice, dogs, non-human primates and humans displayed increases in memory T cells and PD-1 expression, as well as impaired proliferative responses compared to lean controls, indicating a greater degree of T cell exhaustion at baseline. Following immunization with myelin oligodendrocyte glycoprotein, obese mice were resistant to induction of EAE, correlating with reduced antigen-specific CD4 T cells in the central nervous system. Administration of anti-PD-1 resulted in restoration of EAE and increased antigen-specific T cell numbers in obese mice. Tumors in obese mice exhibited accelerated growth compared to lean mice, and T cells displayed higher PD-1 expression correlating with RNAseq/molecular signatures of exhaustion compared to tumor-bearing lean mice. PD-1 blockade resulted in marked anti-tumor effects only in obese mice, and not lean. Impaired viral resistance to murine cytomegalovirus (MCMV) resulted was seen in obese mice, associated with increased PD-1/PD-L1 expression, which was reversible by PD-1/PD-L1 blockade. Conclusions: Obesity results in an increase in PD-1/PD-L1 expression and inhibition of T cell responses across species, and blockade not only reverses this inhibition but also leads to markedly augmented T cell effector responses compared to lean counterparts where no effects were observed. These results highlight how the immune system has evolved to control T cell responses using checkpoints contingent on dynamic host conditions and have translational relevance for predicting both efficacy and toxicity in clinical immuno-oncology.

scholarly journals Multiple Epitopes in the Murine Cytomegalovirus Early Gene Product M84 Are Efficiently Presented in Infected Primary Macrophages and Contribute to Strong CD8+-T-Lymphocyte Responses and Protection following DNA Immunization

2004 ◽  
Vol 78 (20) ◽  
pp. 11233-11245 ◽  
Author(s):  
Ming Ye ◽  
Christopher S. Morello ◽  
Deborah H. Spector
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
T Cell Responses ◽  
Dna Vaccination ◽  
Early Gene ◽  
Murine Cytomegalovirus ◽  
Specific Response ◽  
Mcmv Infection ◽  
Cell Responses

ABSTRACT We previously demonstrated that after vaccination of BALB/c mice with DNA encoding murine cytomegalovirus (MCMV) IE1 or M84, a similar level of protection against MCMV infection was achieved. However, the percentage of antigen-specific CD8+ T cells elicited by IE1 was higher than that by M84 as measured by intracellular cytokine staining when splenocytes were stimulated with an epitope peptide (M. Ye at al., J. Virol. 76:2100-2112, 2002). We show here that after DNA vaccination with M84, a higher percentage of M84-specific CD8+ T cells was detected when splenocytes were stimulated with J774 cells expressing full-length M84. When the defined M84 epitope 297-305 was deleted, the mutant DNA vaccine was still protective against MCMV replication and induced strong M84-specific CD8+-T-cell responses. The M84 gene was subsequently subcloned into three fragments encoding overlapping protein fragments. When mice were immunized with each of the M84 subfragment DNAs, at least two additional protective CD8+-T-cell epitopes were detected. In contrast to strong responses after DNA vaccination, M84-specific CD8+-T-cell responses were poorly induced during MCMV infection. The weak M84-specific response after MCMV infection was not due to poor antigen presentation in antigen-presenting cells, since both J774 macrophages and primary peritoneal macrophages infected with MCMV in vitro were able to efficiently and constitutively present M84-specific epitopes starting at the early phase of infection. These results indicate that antigen presentation by macrophages is not sufficient for M84-specific CD8+-T-cell responses during MCMV infection.

scholarly journals Human Gastro-Intestinal Graft-Versus-Host Disease Is Mediated By Retinoic Acid-Responsive CD8+ Effector T-Cells Under IL-23 Polarising Conditions

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 77-77
Author(s):  
Jennifer A Ball ◽  
Andrew James Clear ◽  
Maria Calaminici ◽  
Andrew Stagg ◽  
James Lindsay ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Subset ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Tissue Level ◽  
Cell Responses ◽  
Severe Stage ◽  
Skin Biopsies ◽  
The Impact

Abstract Background: Gastro-intestinal (GI) graft-versus-host disease (GvHD) results in significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation (AHSCT). Retinoic acid (RA), a metabolite of vitamin A, has diverse effects on immune cells. RA signaling promotes immune tolerance under steady state conditions. However in pro-inflammatory conditions RA increases Th1, Th17 CD4+ and Tc1 CD8+ T cell responses and is implicated in the pathogenesis of autoimmune inflammatory bowel disease. Furthermore, RA exposure and RA-receptor alpha (RARα) signaling in allogeneic T cells potentiates GI-GvHD in mice. Thus RA and cytokines that influence the effect of RA on T cells may represent potential therapeutic targets for GI-GvHD. However, the impact of RA at a tissue level in human GI-GvHD is unknown. We therefore investigated the role of RA-responsive T cells in human GvHD in vivo and human allogeneic T-cell responses in vitro . Methods: We scrutinized GI biopsies from 47 patients after AHSCT (36 with and 11 without GI-GvHD confirmed by conventional histological criteria). We also analysed skin biopsies from 11 AHSCT patients. We used conventional immunohistochemistry and a novel deep phenotyping method using sequential staining, stripping and re-probing on the same fixed embedded biopsy to determine cellular co-expression of multiple markers to identify RA-responsive T cells in human GvHD biopsies at sites of GvHD damage. Finally, we used an HLA-mismatched allogeneic mixed lymphocyte co-culture (MLRs) system, combining CFSE dye dilution and multi-parameter flow cytometry to enable the phenotyping of alloproliferative T cells after manipulation of RA signalling. Results: Firstly we observed thatthe number of cells expressing high levels of cytoplasmic RA binding proteins I/II (a surrogate marker of RA) was increased in gut biopsies in patients with GI-GvHD versus controls (median 155 vs 43 cells/mm2, p=0.056). Importantly the number of cells expressing RARα was also significantly increased (median 1315 vs 544 cells/mm2, p=0.001) consistent with RA-responsiveness. Crucially the number of RARα+ cells correlated with clinical stage of acute GI-GvHD with higher numbers in patients with severe (stage 3-4) versus less severe (stage 1-2) disease. Having demonstrated that RA-responsive cells were associated with both occurrence and severity of GI-GvHD we went on to identify potential RA-responsive T cell subsets. Additionally, as IL-23 and IL-33 direct RA-programming of T cells to either pro-inflammatory or tolerogenic phenotypes we also measured cellular expression of these cytokines and their receptors. CD8+ T cells co-localized with RARα+ cells and were present in significantly increased numbers in gut biopsies from patients with GI-GvHD, as were Tbet+ Th1/Tc1 cells. In contrast, numbers of RORγ+ Th17 cells were unchanged and CD4+ cells were decreased. IL-23p19+ and IL-23R+ cell numbers were significantly increased in GI-GvHD biopsies, whereas IL33R (ST2+)cells were unchanged. In order to determine if the RA-responsive, CD8+ and IL-23R+ cells represented a single effector subset, we used sequential stripping/re-probing to deep phenotype the T cells. We identified a unique single CD8+ T-cell population that co-expressed RARα+, T-bet and IL23R, present in significantly increased numbers in gut biopsies from patients with GI-GvHD versus controls. This is consistent with a RA-responsive, IL-23-dependent, inflammatory Tc1 effector cell mediating tissue damage in human gut GvHD. Importantly, there was no increase in this T cell subset in skin biopsies of skin GvHD patients demonstrating tissue-specificity. Finally we determined the impact of exogenous RA exposure on T cell alloresponses in MLRs. RA significantly increased the proportion of alloproliferative effector CD8+ T cells co-expressing Tbet and gut-homing molecules, confirming that RA can directly potentiate human alloreactive CD8 T cell responses with capacity to home to the GI tract. Conclusions: This is the first data to demonstrate a role for RA at a tissue level in human GI-GvHD. Furthermore we have identified a gut specific CD8+ T cell subset which co-expresses RARα, T-bet, and IL-23R localised in areas of GI-damage likely to represent the RA-responsive effector cell. Therapeutic blockade of IL-23R could target this cellular response to prevent or treat GI-GvHD. Disclosures Gribben: Acerta: Honoraria; Janssen: Honoraria; Kite: Honoraria; Celgene: Honoraria; TG Therapeutics: Honoraria; Karyopharm: Honoraria; Pharmacyclics: Honoraria; Genentech/Roche: Honoraria; Abbvie: Honoraria.

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.

scholarly journals TNFRSF14 aberrations in Follicular Lymphoma B Cells Result in Increased Alloresponses in Vitro and in Vivo

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2426-2426 ◽  
Author(s):  
Eleni Kotsiou ◽  
Jessica Okosun ◽  
Andrew James Clear ◽  
Sameena Iqbal ◽  
Jude Fitzgibbon ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Lymph Nodes ◽  
Follicular Lymphoma ◽  
T Cell Responses ◽  
Cell Responses ◽  
Significant Difference ◽  
The Impact

Abstract Introduction Genetic aberrations of Tumor Necrosis Factor Receptor Superfamily 14 (TNFRSF14, also known as HVEM) have been shown to occur at high frequencies in patients (pts) with follicular lymphoma (FL). HVEM is a ligand for B and T lymphocyte attenuator (BTLA) which negatively regulates T cell responses and BTLA stimulation reduces acute graft-versus-host disease (aGvHD) in murine allogeneic hematopoietic cell transplantation (AHCT) models. As activated FL B cells are potent alloantigen presenting cells, we hypothesized that TNFRSF14 aberrations in FL B cells would reduce expression of HVEM and potentiate capacity of FL B cells to stimulate allogeneic T cell responses. We therefore sought to determine the functional effect of TNFRSF14 aberrations on FL B cell-stimulated donor T cell alloresponses in vitro. We also examined the impact of TNFRSF14 aberrations on the outcome of FL pts after HLA-matched reduced intensity conditioning (RIC) AHCT. Results FL B cells from lymph nodes were FACS-sorted (>90% purity and > 95% light chain restriction), activated and used as stimulators in mixed lymphocyte reactions with purified allogeneic responder CD3+ T cells. HVEM expression on FL B cells from pts with biallelic TNFRSF14 aberrations (Mut/Del cases) was undetectable whereas 40% of FL B cells from TNFRSF14 WT cases expressed HVEM (Fig 1 A). In contrast, FL B cells from Mut/Del and WT cases expressed similar levels of MHC class I/II, CD80, CD86 and CD58 before and after activation. Allostimulation with Mut/Del FL B cells resulted in significantly greater expression of activation markers on responder CD4+ T cells, increased secretion of pro-inflammatory cytokines (IFN-γ, TNF-α, and IL-2) measured by ELISA and increased frequencies of cytokine-secreting CD4+ and CD8+ T cells enumerated by intracellular cytokine staining. Responder T cell proliferation by thymidine incorporation was significantly greater after stimulation with Mut/Del FL B cells compared to WT FL B cells. CFSE labeling studies demonstrated that this effect resulted from increased proliferation of CD4+ and CD8+ responder T cells after both primary (Fig 1B) and secondary allostimulation. To determine if the increased alloresponses we observed using FL B cells from TNFRSF14 Mut/Del cases was due to reduced HVEM-BTLA signaling, we performed allogeneic co-cultures in the presence of antagonist or agonist BTLA antibodies (ab). Antagonist anti-BTLA ab increased proliferation of responder T cells after stimulation with WT FL B cells confirming that BTLA limits alloresponses in our in vitro model. Importantly, agonist BTLA ab reduced alloresponses stimulated by Mut/Del FL B cells. We next sought to determine if the increased alloresponses we detected in vitro in FL pts with TNFRSF14 aberrations resulted in an increase in clinical alloreactivity after AHCT. DNA from lymph nodes from FL pts undergoing T-cell replete RIC AHSCT was screened for TNFRSF14 mutations and deletions by Sanger sequencing and multiplex ligation-probe amplification respectively. Cumulative incidences (CI) of aGvHD and GvHD-related death were calculated with FL progression as a competing risk. TNFRSF14 aberrations were identified in 10/21 pts prior to RIC AHCT (4 Mut/Del, 1 Del/Del, 1 Mut/WT, 4 Del/WT). Most (18/21) pts had evidence of ongoing FL pre-transplant. Disease and donor characteristics were similar in pts with and without aberrations. There was no significant difference in CI of aGvHD in pts with or without TNFRSF14 aberrations. However there was a significantly higher CI of fatal aGvHD in patients with TNFRSF14 aberrations (45%) compared to those without aberrations (0%, p<0.01). Interestingly, relapse was less frequent in patients with TNFRSF14 aberrations consistent with increased graft-versus-tumor effects, although this did not reach statistical significance. Conclusion This study is the first to describe the impact of TNFRSF14 aberrations on the allostimulatory capacity of FL B cells. TNFRSF14 aberrations were associated with enhanced T-cell alloresponses in vitro and increased death from aGvHD. Importantly, our results suggest FL patients with TNFRSF14 aberrations may benefit from more aggressive immunosuppression to prevent fatal aGvHD after AHCT. The increased antigen-presenting capacity of FL B cells with TNFRSF14 aberrations could also influence autologous anti-tumor responses and impact outcome after other treatment modalities. Figure 1 Figure 1. Disclosures Gribben: Celgene: Research Funding; Pharmacyclics: Honoraria; Roche: Honoraria.

scholarly journals Th1 Dominant Nucleocapsid and Spike Antigen-Specific CD4+ and CD8+ Memory T Cell Recall Induced by hAd5 S-Fusion + N-ETSD Infection of Autologous Dendritic Cells from Patients Previously Infected with SARS-CoV-2

2020 ◽  
Author(s):  
Peter Sieling ◽  
Lise Zakin ◽  
Annie Shin ◽  
Brett Morimoto ◽  
Helty Adisetiyo ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Viral Neutralization ◽  
Cell Responses ◽  
Infected Cells

ABSTRACTTo address the need for a safe, efficacious vaccine against SARS-CoV-2 infection with the critical properties of enabling both blocking viral entry into cells and clearing virus from cells already infected, we have developed a bivalent, human adenovirus serotype 5 (hAd5) SARS-CoV- 2 S-Fusion + N-ETSD vaccine that is currently in clinical testing. This vaccine uses the next- generation hAd5 [E1-, E2b-, E3-] platform previously used successfully in cancer patients with pre-existing adenovirus immunity, engineered to express both SARS-CoV-2 spike (S) protein modified to improve the generation of neutralizing antibodies to block entry of the virus, and nucleocapsid (N) protein with an Enhanced T cell Stimulation Domain (ETSD) to activate CD4+ and CD8+ T cells to clear the virus and block replication by killing infected cells. The targeting of N to endosomes and lysosomes to enhance CD4+ and CD8+ T-cell responses distinguishes our vaccine. In our previously reported pre-clinical studies we showed that in mice, the hAd5 S-Fusion + N-ETSD vaccine elicits both humoral and T-cell responses that are robust and T helper cell 1 (Th1) dominant. Here we report that the hAd5 S-Fusion + N-ETSD vaccine is recognized by anti-sera and T cells from previously SARS-CoV-2 infected patients, and that the presence of N is vital for T-cell recall. The findings presented herein: (i) demonstrate specific recognition of hAd5 S-Fusion + N-ETSD infected cells by plasma antibodies from previously SARS-CoV-2 infected patients, but not antibodies from virus-naïve subjects; (ii) show enhanced binding of plasma SARS-CoV-2 antibodies from previously infected patients to monocyte-derived dendritic cells (MoDCs) expressing the hAd5 S-Fusion + N-ETSD vaccine as compared to hAd5 S-Fusion alone; (iii) reveal N-ETSD localizes to vesicles associated with MHC class II antigen presentation, including endosomes, lysosomes and autophagosomes in MoDCs; (iv) demonstrate endosome/lysosome-targeted N-ETSD elicits higher interferon-γ T-cell responses than cytoplasm-localized N; and (v) N-ETSD alone or in the hAd5 S-Fusion + N-ETSD construct induces both CD4+ and CD8+ T cell memory recall. This recognition of hAd5 S-Fusion + N-ETSD vaccine antigens by T cells from previously SARS-CoV-2 infected patients, together with the ability of this vaccine candidate to elicit de novo immune responses in naïve mice suggests that it re-capitulates the natural immune response to SARS-CoV-2 to activate both B and T cells towards viral neutralization and recognition of infected cells, critical for prevention of COVID-19 disease. Intriguingly, our hAd5 S-Fusion + N-ETSD T-cell biased vaccine has the potential to not only provide protection for uninfected individuals, but also to be utilized as a therapeutic for already infected patients to induce rapid clearance of the virus by activating T cells to kill the virus-infected cells, thereby reducing viral replication and lateral transmission.

scholarly journals Modulation of MHC-E transport by viral decoy ligands is required for RhCMV/SIV vaccine efficacy

2020 ◽  
Author(s):  
Marieke Verweij ◽  
Scott G. Hansen ◽  
Ravi Iyer ◽  
Nessy John ◽  
Daniel Malouli ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vaccine Efficacy ◽  
Rhesus Macaques ◽  
T Cell Responses ◽  
Functional Differentiation ◽  
Peptide Epitopes ◽  
Mhc Ii ◽  
Cell Responses ◽  
Infected Cells

AbstractStrain 68-1 rhesus cytomegalovirus (RhCMV) vectors expressing simian immunodeficiency virus (SIV) antigens elicit CD8+ T cells that recognize peptide epitopes presented by major histocompatibility complex (MHC)-II and MHC-E molecules, instead of MHC-Ia, and are uniquely able to mediate stringent control and subsequent clearance of highly pathogenic SIV in ∼50% of vaccinated rhesus macaques (RMs). We show that the MHC-E ligand VMAPRTLLL (VL9), encoded by the Rh67 gene (or its HCMV UL40 counterpart) is required for recognition of RhCMV-infected fibroblasts by MHC-E-restricted CD8+ T cells via its ability to promote intracellular MHC-E transport. Moreover, deletion of Rh67 from 68-1 RhCMV/SIV vectors, or mutation of its embedded VL9 ligand, abrogated induction of MHC-E-restricted CD8+ T cell responses, leaving responses that exclusively target MHC-II-restricted epitopes. These MHC-II-presented CD8+ T cell responses, though comparable in response magnitude and functional differentiation to responses arising from the efficacious 68-1 vector, did not protect RMs against SIV challenge, indicating that Rh67/UL40-enabled direct priming of MHC-E-targeted CD8+ T cells is a crucial element of RhCMV/SIV vaccine efficacy.One Sentence SummaryA cytomegalovirus protein (Rh67/UL40) that upregulates MHC-E expression on RhCMV/SIV-vector infected cells is required for induction of MHC-E-restricted CD8+ T cells and for protection against SIV.

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