scholarly journals Immunization with a Mixture of HIV Env DNA and VLP Vaccines Augments Induction of CD8 T Cell Responses

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Ling Ye ◽  
Zhiyuan Wen ◽  
Ke Dong ◽  
Lei Pan ◽  
Zhigao Bu ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Dna Vaccine ◽  
Cell Response ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Antibody Responses ◽  
Cell Responses ◽  
Virus Like Particle

The immune response induced by immunization with HIV Env DNA and virus-like particle (VLP) vaccines was investigated. Immunization with the HIV Env DNA vaccine induced a strong CD8 T cell response but relatively weak antibody response against the HIV Env whereas immunization with VLPs induced higher levels of antibody responses but little CD8 T cell response. Interestingly, immunization with a mixture the HIV Env DNA and VLP vaccines induced enhanced CD8 T cell and antibody responses. Further, it was observed that the mixing of DNA and VLP vaccines during immunization is necessary for augmenting induction of CD8 T cell responses and such augmentation of CD8 T cell responses was also observed by mixing the HIV Env DNA vaccine with control VLPs. These results show that immunization with a mixture of DNA and VLP vaccines combines advantages of both vaccine platforms for eliciting high levels of both antibody and CD8 T cell responses.

scholarly journals Role of Thymic Output in Regulating CD8 T-Cell Homeostasis during Acute and Chronic Viral Infection

2005 ◽  
Vol 79 (15) ◽  
pp. 9419-9429 ◽  
Author(s):  
Nicole E. Miller ◽  
Jennifer R. Bonczyk ◽  
Yumi Nakayama ◽  
M. Suresh
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
Viral Infections ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Responses ◽  
Lcmv Infection

ABSTRACT Although it is well documented that CD8 T cells play a critical role in controlling chronic viral infections, the mechanisms underlying the regulation of CD8 T-cell responses are not well understood. Using the mouse model of an acute and chronic lymphocytic choriomeningitis virus (LCMV) infection, we have examined the relative importance of peripheral T cells and thymic emigrants in the elicitation and maintenance of CD8 T-cell responses. Virus-specific CD8 T-cell responses were compared between mice that were either sham thymectomized or thymectomized (Thx) at ∼6 weeks of age. In an acute LCMV infection, thymic deficiency did not affect either the primary expansion of CD8 T cells or the proliferative renewal and maintenance of virus-specific lymphoid and nonlymphoid memory CD8 T cells. Following a chronic LCMV infection, in Thx mice, although the initial expansion of CD8 T cells was normal, the contraction phase of the CD8 T-cell response was exaggerated, which led to a transient but striking CD8 T-cell deficit on day 30 postinfection. However, the virus-specific CD8 T-cell response in Thx mice rebounded quickly and was maintained at normal levels thereafter, which indicated that the peripheral T-cell repertoire is quite robust and capable of sustaining an effective CD8 T-cell response in the absence of thymic output during a chronic LCMV infection. Taken together, these findings should further our understanding of the regulation of CD8 T-cell homeostasis in acute and chronic viral infections and might have implications in the development of immunotherapy.

scholarly journals Listeria Monocytogenes: A Model Pathogen Continues to Refine Our Knowledge of the CD8 T Cell Response

Pathogens ◽  
2018 ◽  
Vol 7 (2) ◽  
pp. 55 ◽  
Author(s):  
Zhijuan Qiu ◽  
Camille Khairallah ◽  
Brian Sheridan
Keyword(s):  
Listeria Monocytogenes ◽  
T Cell ◽  
Cell Response ◽  
Protective Immunity ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Oral Infection ◽  
T Cell Response ◽  
Infection Model ◽  
Cell Responses

Listeria monocytogenes (Lm) infection induces robust CD8 T cell responses, which play a critical role in resolving Lm during primary infection and provide protective immunity to re-infections. Comprehensive studies have been conducted to delineate the CD8 T cell response after Lm infection. In this review, the generation of the CD8 T cell response to Lm infection will be discussed. The role of dendritic cell subsets in acquiring and presenting Lm antigens to CD8 T cells and the events that occur during T cell priming and activation will be addressed. CD8 T cell expansion, differentiation and contraction as well as the signals that regulate these processes during Lm infection will be explored. Finally, the formation of memory CD8 T cell subsets in the circulation and in the intestine will be analyzed. Recently, the study of CD8 T cell responses to Lm infection has begun to shift focus from the intravenous infection model to a natural oral infection model as the humanized mouse and murinized Lm have become readily available. Recent findings in the generation of CD8 T cell responses to oral infection using murinized Lm will be explored throughout the review. Finally, CD8 T cell-mediated protective immunity against Lm infection and the use of Lm as a vaccine vector for cancer immunotherapy will be highlighted. Overall, this review will provide detailed knowledge on the biology of CD8 T cell responses after Lm infection that may shed light on improving rational vaccine design.

scholarly journals Public T-cell epitopes shared among SARS-CoV-2 variants are presented on prevalent HLA class I alleles

2021 ◽  
Author(s):  
Saskia Meyer ◽  
Isaac Blaas ◽  
Ravi Chand Bollineni ◽  
Marina Delic-Sarac ◽  
Trung T Tran ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Response ◽  
T Cell Responses ◽  
Hla Class I ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Class I ◽  
T Cell Epitopes ◽  
Low Frequencies ◽  
Cell Responses

T-cell epitopes with broad population coverage may form the basis for a new generation of SARS-CoV-2 vaccines. However, published studies on immunoprevalence are limited by small test cohorts, low frequencies of antigen-specific cells and lack of data correlating eluted HLA ligands with T-cell responsiveness. Here, we investigate CD8 T-cell responses to 48 peptides eluted from prevalent HLA alleles, and an additional 84 predicted binders, in a large cohort of convalescents (n=83) and pre-pandemic control samples (n=19). We identify nine conserved SARS-CoV-2 specific epitopes restricted by four of the most prevalent HLA class I alleles in Caucasians, to which responding CD8 T cells are detected in 70-100% of convalescents expressing the relevant HLA allele, including two novel epitopes. We find a strong correlation between immunoprevalence and immunodominance. Using a new algorithm, we predict that a vaccine including these epitopes would induce a T cell response in 83% of Caucasians. Significance Statement: Vaccines that induce broad T-cell responses may boost immunity as protection from current vaccines against SARS-CoV-2 is waning. From a manufacturing standpoint, and to deliver the highest possible dose of the most immunogenic antigens, it is rational to limit the number of epitopes to those inducing the strongest immune responses in the highest proportion of individuals in a population. Our data show that the CD8 T cell response to SARS-CoV-2 is more focused than previously believed. We identify nine conserved SARS-CoV-2 specific CD8 T cell epitopes restricted by four of the most prevalent HLA class I alleles in Caucasians and demonstrate that seven of these are endogenously presented.

The Response to Repeated Vaccination with PR1 and WT1 Peptides Admixed in Montanide Adjuvant Is Transient and Fails to Induce Sustained Anti-Leukemia Responses in Patients with Myeloid Malignancies.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4096-4096
Author(s):  
Katayoun Rezvani ◽  
Agnes S. M. Yong ◽  
Stephan Mielke ◽  
Behnam Jafarpour ◽  
Bipin N. Savani ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Gm Csf ◽  
Cell Responses ◽  
Ifn Γ

Abstract Abstract 4096 Poster Board III-1031 We previously demonstrated the immunogenicity of a combined vaccine approach employing two leukemia-associated antigenic peptides, PR1 and WT1 (Rezvani Blood 2008). Eight patients with myeloid malignancies received one subcutaneous 0.3 mg and 0.5 mg dose each of PR1 and WT1 vaccines in Montanide adjuvant, with 100 μg of granulocyte-macrophage colony-stimulating factor (GM-CSF). CD8+ T-cell responses against PR1 or WT1 were detected in all patients as early as 1 week post-vaccination. However, responses were only sustained for 3-4 weeks. The emergence of PR1 or WT1-specific CD8+ T-cells was associated with a significant but transient reduction in minimal residual disease (MRD) as assessed by WT1 expression, suggesting a vaccine-induced anti-leukemia response. Conversely, loss of response was associated with reappearance of WT1 transcripts. We hypothesized that maintenance of sustained or at least repetitive responses may require frequent boost injections. We therefore initiated a phase 2 study of repeated vaccination with PR1 and WT1 peptides in patients with myeloid malignancies. Five patients with acute myeloid leukemia (AML) and 2 patients with myelodysplastic syndrome (MDS) were recruited to receive 6 injections at 2 week intervals of PR1 and WT1 in Montanide adjuvant, with GM-CSF as previously described. Six of 7 patients completed 6 courses of vaccination and follow-up as per protocol, to monitor toxicity and immunological responses. Responses to PR1 or WT1 vaccine were detected in all patients after only 1 dose of vaccine. However, additional boosting did not further increase the frequency of PR1 or WT1-specific CD8+ T-cell response. In 4/6 patients the vaccine-induced T-cell response was lost after the fourth dose and in all patients after the sixth dose of vaccine. To determine the functional avidity of the vaccine-induced CD8+ T-cell response, the response of CD8+ T-cells to stimulation with 2 concentrations of PR1 and WT1 peptides (0.1 and 10 μM) was measured by IC-IFN-γ staining. Vaccination led to preferential expansion of low avidity PR1 and WT1 specific CD8+ T-cell responses. Three patients (patients 4, 6 and 7) returned 3 months following the 6th dose of PR1 and WT1 peptide injections to receive a booster vaccine. Prior to vaccination we could not detect the presence of PR1 and WT1 specific CD8+ T-cells by direct ex-vivo tetramer and IC-IFN-γ assay or with 1-week cultured IFN-γ ELISPOT assay, suggesting that vaccination with PR1 and WT1 peptides in Montanide adjuvant does not induce memory CD8+ T-cell responses. This observation is in keeping with recent work in a murine model where the injection of minimal MHC class I binding peptides derived from self-antigens mixed with IFA adjuvant resulted in a transient effector CD8+ T cell response with subsequent deletion of these T cells and failure to induce CD8+ T cell memory (Bijker J Immunol 2007). This observation can be partly explained by the slow release of vaccine peptides from the IFA depot without systemic danger signals, leading to presentation of antigen in non-inflammatory lymph nodes by non-professional antigen presenting cells (APCs). An alternative explanation for the transient vaccine-induced immune response may be the lack of CD4+ T cell help. In summary these data support the immunogenicity of PR1 and WT1 peptide vaccines. However new approaches will be needed to induce long-term memory responses against leukemia antigens. To avoid tolerance induction we plan to eliminate Montanide adjuvant and use GM-CSF alone. Supported by observations that the in vivo survival of CD8+ T-effector cells against viral antigens are improved by CD4+ helper cells, we are currently attempting to induce long-lasting CD8+ T-cell responses to antigen by inducing CD8+ and CD4+ T-cell responses against class I and II epitopes of WT1 and PR1. Disclosures: No relevant conflicts of interest to declare.

EBV-positive lymphoma patients have a selective deficiency in EBV immunity

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 21032-21032
Author(s):  
K. N. Heller ◽  
P. G. Steinherz ◽  
C. S. Portlock ◽  
C. Münz
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Healthy Volunteers ◽  
Cell Response ◽  
T Cell Responses ◽  
T Cell Response ◽  
Specific Immune Response ◽  
Cell Responses

21032 Background: Epstein-Barr virus (EBV) asymptomatically establishes persistent infections in more than 90% of the adult population. However, due to effective immune control, only a minority of infected carriers develops spontaneous EBV-associated lymphomas. Since EBV nuclear antigen-1 (EBNA1) is the only protein expressed in all proliferating EBV infected cells we hypothesize that EBNA1 specific immune response is critical in preventing EBV-positive lymphomas. Methods: After informed consent, peripheral blood from healthy volunteers and lymphoma patients (prior to therapy- no evidence of cytopenia) were stimulated (ex vivo) with overlapping peptides covering the immunogenic EBNA1 (aa400–641) sequence. Frequency of EBNA1-specific T-cells were assessed by intracellular cytokine staining and flow cytometric proliferation assays. Cytokine pattern, surface marker phenotype and functional reactivity against EBV specific and control antigens were analyzed. Results: Patient and volunteer immune responses to control antigens and other viruses were assessed and statistically indistinguishable. EBNA1 specific CD4+ T cell responses were detected among 18 of 20 healthy carriers, and among 10 of 16 patients with EBV-negative lymphoma (relative to healthy volunteers p=0.145 via paired student T test). None of the patients with EBV-positive lymphomas (n=8) had a detectable EBNA1-specific CD4+ T-cell response (p<0.003 relative to healthy volunteers and patients with EBV-negative lymphomas). Conclusions: Healthy volunteers and patients with EBV-negative lymphoma have statistically similar EBNA1-specific CD4+ T cell responses. Although patients with EBV-positive lymphoma have intact immune responses to common viruses and antigens, they selectively lack an EBNA1-specific CD4+ T cell response. An intact EBNA1 specific immune response among patients with EBV-negaitve lymphoma implies that lymphoma is not a cause of a selective immune deficiency. On the contrary, these findings suggest that EBNA1-specific CD4+ T cells are critical in the prevention of EBV mediated lymphomas, and a defect in EBNA1 specific immunity may leave EBV carriers suseptible to EBV-positive lymphomas. EBNA1- specific CD4+ T cell function may be a new target for therapies of EBV-associated malignancies. No significant financial relationships to disclose.

scholarly journals CD4+ T Cells Induced by a DNA Vaccine: Immunological Consequences of Epitope-Specific Lysosomal Targeting

2001 ◽  
Vol 75 (21) ◽  
pp. 10421-10430 ◽  
Author(s):  
Fernando Rodriguez ◽  
Stephanie Harkins ◽  
Jeffrey M. Redwine ◽  
Jose M. de Pereda ◽  
J. Lindsay Whitton
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dna Vaccine ◽  
Cell Response ◽  
T Cell Responses ◽  
Lymphocytic Choriomeningitis ◽  
Lymphocytic Choriomeningitis Virus ◽  
T Cell Response ◽  
Cell Responses ◽  
Lysosomal Targeting

ABSTRACT Our previous studies have shown that targeting DNA vaccine-encoded major histocompatibility complex class I epitopes to the proteasome enhanced CD8+ T-cell induction and protection against lymphocytic choriomeningitis virus (LCMV) challenge. Here, we expand these studies to evaluate CD4+ T-cell responses induced by DNA immunization and describe a system for targeting proteins and minigenes to lysosomes. Full-length proteins can be targeted to the lysosomal compartment by covalent attachment to the 20-amino-acid C-terminal tail of lysosomal integral membrane protein-II (LIMP-II). Using minigenes encoding defined T-helper epitopes from lymphocytic choriomeningitis virus, we show that the CD4+T-cell response induced by the NP309–328 epitope of LCMV was greatly enhanced by addition of the LIMP-II tail. However, the immunological consequence of lysosomal targeting is not invariably positive; the CD4+ T-cell response induced by the GP61–80 epitope was almost abolished when attached to the LIMP-II tail. We identify the mechanism which underlies this marked difference in outcome. The GP61–80 epitope is highly susceptible to cleavage by cathepsin D, an aspartic endopeptidase found almost exclusively in lysosomes. We show, using mass spectrometry, that the GP61–80 peptide is cleaved between residues F74 and K75 and that this destroys its ability to stimulate virus-specific CD4+ T cells. Thus, the immunological result of lysosomal targeting varies, depending upon the primary sequence of the encoded antigen. We analyze the effects of CD4+ T-cell priming on the virus-specific antibody and CD8+ T-cell responses which are mounted after virus infection and show that neither response appears to be accelerated or enhanced. Finally, we evaluate the protective benefits of CD4+ T-cell vaccination in the LCMV model system; in contrast to DNA vaccine-induced CD8+ T cells, which can confer solid protection against LCMV challenge, DNA vaccine-mediated priming of CD4+ T cells does not appear to enhance the vaccinee's ability to combat viral challenge.

scholarly journals The Th1 Immune Response to Plasmodium falciparum Circumsporozoite Protein Is Boosted by Adenovirus Vectors 35 and 26 with a Homologous Insert

2010 ◽  
Vol 17 (11) ◽  
pp. 1687-1694 ◽  
Author(s):  
Katarina Radošević ◽  
Ariane Rodriguez ◽  
Angelique A. C. Lemckert ◽  
Marjolein van der Meer ◽  
Gert Gillissen ◽  
...  
Keyword(s):  
Immune Response ◽  
Plasmodium Falciparum ◽  
T Cell ◽  
Cell Response ◽  
T Cell Responses ◽  
T Cell Response ◽  
Virus Surface ◽  
Cell Responses ◽  
Ifn Γ ◽  
Th1 Immune Response

ABSTRACT The most advanced malaria vaccine, RTS,S, is comprised of an adjuvant portion of the Plasmodium falciparum circumsporozoite (CS) protein fused to and admixed with the hepatitis B virus surface antigen. This vaccine confers short-term protection against malaria infection, with an efficacy of about 50%, and induces particularly B-cell and CD4+ T-cell responses. In the present study, we tested by the hypothesis that the Th1 immune response to CS protein, in particular the CD8+ T-cell response, which is needed for strong and lasting malaria immunity, is boosted to sustainable levels vectors adenovirus and 26 with an homologous insert 35 (Ad35.CS/Ad26.CS). In this study, we evaluated immune responses induced with vaccination regimens based on an adjuvant-containing, yeast-produced complete CS protein followed by two recombinant low-seroprevalence adenoviruses expressing P. falciparum CS antigen, Ad35.CS (subgroup B) and Ad26.CS (subgroup D). Our results show that (i) the yeast (Hansenula polymorpha)produced, adjuvanted full-length CS protein is highly potent in inducing high CS-specific humoral responses in mice but produces poor T-cell responses, (ii) the Ad35.CS vector boosts the gamma interferon-positive (IFN-γ+) CD8+ T-cell response induced by the CS protein immunization and shifts the immune response toward the Th1 type, and (iii) a three-component heterologous vaccination comprised of a CS protein prime followed by boosts with Ad35.CS and Ad26.CS elicits an even more robust and sustainable IFN-γ+ CD8+ T-cell response than one- or two-component regimens. The Ad35.CS/Ad26.CS combination boosted particularly the IFN-γ+ and tumor necrosis factor alpha-positive (TNF-α+) T cells, confirming the shift of the immune response from the Th2 type to the Th1 type. These results support the notion of first immunizations of infants with an adjuvanted CS protein vaccine, followed by a booster Ad35.CS/Ad26.CS vaccine at a later age, to induce lasting protection against malaria for which the Th1 response and immune memory is required.

scholarly journals DIFFERENTIAL IMMUNODOMINANCE HIERARCHY OF CD8+ T CELL RESPONSES IN HLA-B*27:05 AND B*27:02-MEDIATED CONTROL OF HIV-1 INFECTION

2017 ◽  
pp. JVI.01685-17
Author(s):  
Emily Adland ◽  
Matilda Hill ◽  
Nora Lavandier ◽  
Anna Csala ◽  
Anne Edwards ◽  
...  
Keyword(s):  
T Cell ◽  
Disease Progression ◽  
Cell Response ◽  
Selection Pressure ◽  
Cell Activity ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Hiv Disease ◽  
Cell Responses

The well-characterised association between HLA-B*27:05 and protection against HIV disease progression has been linked to immunodominant HLA-B*27:05-restricted CD8+ T-cell responses towards the conserved Gag 263-272 (‘KK10’) and Pol 901-909 ‘KY9’ epitopes. We here studied the impact of the 3 amino acid differences between HLA-B*27:05 and the closely-related HLA-B*27:02 on the HIV-specific CD8+ T-cell response hierarchy and on immune control of HIV. Genetic epidemiological data indicate that both HLA-B*27:02 and HLA-B*27:05 associate with slower disease progression and lower viral loads. The effect of HLA-B*27:02 appears consistently stronger than that of HLA-B*27:05. In contrast to HLA-B*27:05, the immunodominant HIV-specific HLA-B*27:02-restricted CD8+ T-cell response is to a Nef epitope (residues 142-150, ‘VW9’), with Pol-KY9 subdominant and Gag-KK10 further subdominant. This selection was driven by structural differences in the F-pocket, mediated by a polymorphism between these two HLA alleles at position 81. Analysis of autologous virus sequences showed that in HLA-B*27:02-positive subjects all three of these CD8+ T-cell responses impose selection pressure on the virus, whereas in HLA-B*27:05-positive subjects there is no Nef-VW9-mediated selection pressure. These studies demonstrate that HLA-B*27:02 mediates protection against HIV disease progression that is at least as strong or stronger than that mediated by HLA-B*27:05. In combination with the protective Gag-KK10 and Pol-KY9 CD8+ T-cell responses that dominate HIV-specific CD8+ T-cell activity in HLA-B*27:05-positive subjects, a Nef-VW9-specific response is additionally present and immunodominant in HLA-B*27:02-positive subjects, mediated through a polymorphism at residue 81 in the F-pocket, that contributes to selection pressure against HIV.IMPORTANCECD8+ T-cells play a central role in successful control of HIV infection, and have the potential also to mediate the eradication of viral reservoirs of infection. The principal means by which ‘protective’ HLA class I molecules, such as HLA-B*27:05 and HLA-B*57:01, slow HIV disease progression, is believed to be via the particular HIV-specific CD8+ T cell responses restricted by those alleles. We focus here on HLA-B*27:05, one of the best-characterised ‘protective’ HLA molecules, and the closely-related HLA-B*27:02, which differs by only 3 amino acids, and which has not been well-studied in relation to control of HIV infection. We show that HLA-B*27:02 is also protective against HIV disease progression, but the CD8+ T-cell immunodominance hierarchy of HLA-B*27:02 differs strikingly from that of HLA-B*27:05. These findings indicate that the immunodominant HLA-B*27:02-restricted Nef response adds to protection mediated by the Gag and Pol specificities that dominate anti-HIV CD8+ T-cell activity in HLA-B*27:05-positive subjects.

scholarly journals LB-18. Broad and Prevalent SARS-CoV-2 CD8+ T Cell Response in Recovered COVID-19 Individuals Demonstrates Kinetics of Early Differentiation

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S852-S853
Author(s):  
Hassen Kared ◽  
Evan Bloch ◽  
Andrew Redd ◽  
Alessandra Nardin ◽  
Hermi Sumatoh ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Peptide Epitopes ◽  
Cell Responses ◽  
Candidate Peptide

Abstract Background Understanding the diversity, breadth, magnitude, and functional profile of the T cell response against SARS-CoV-2 in recovered COVID-19 individuals is critical to evaluate the contribution of T cells to produce a potentially protective immune response. Methods We used a multiplexed peptide-MHC tetramer approach to screen a total of 408 SARS-CoV-2 candidate peptide epitopes for CD8+ T cell recognition in a cohort of 30 individuals recovered from COVID-19. The peptides spanned the whole viral genome and were restricted to six prevalent HLA alleles; T cells were simultaneously characterized by a 28-marker phenotypic panel. The evolution of the SARS-CoV-2 T cell responses was then statistically modeled against time from diagnosis, and in relation to humoral and inflammatory response. Workflow for Study. A multiplexed peptide-MHC tetramer approach was used to screen SARS-CoV-2 candidate peptide epitopes in a cohort of 30 COVID-19 recovered patients across 6 prevalent HLA alleles, and T cells profiled with a 28-marker phenotypic panel. Multiplex tetramer screen. One representative COVID-19 recovered patient and one healthy donor were screened for HLA- relevant SARS-CoV-2 epitopes, as well as epitopes for CMV, EBV, Influenza, Adenovirus and MART-1. Shown are the frequencies of tetramer-positive CD8 T cells from 2 technical replicates per subject. Results Almost all individuals screened showed a T cell response against SARS-CoV-2 (29/30): 132 SARS-CoV-2-specific CD8+ T cells hits were detected, corresponding to 52 unique reactive epitopes. Twelve of the 52 unique SARS-CoV-2-specific epitopes were recognized by more than 40% of the individuals screened, indicating high prevalence in the subjects. Importantly, these CD8+ T cell responses were directed against both structural and non-structural viral proteins, with the highest magnitude against nucleocapsid derived peptides, but without any antigen-driven bias in the phenotype of specific T cells. Overall, SARS-CoV-2 T cells showed specific states of differentiation (stem-cell memory and transitional memory), which differed from those of MART-1, influenza, CMV and EBV-specific T cells. UMAP visualization revealed a phenotypic profile of SARS-CoV-2-specific CD8 T cells in COVID-19 convalescent donors that is distinct from other viral specificities, such as influenza, CMV, EBV and Adenovirus. SARS-CoV-2 epitope screening revealed CD8+ T cell responses directed against both structural and non-structural viral proteins, with the highest magnitude response against nucleocapsid derived peptides Conclusion The kinetics modeling demonstrates a dynamic, evolving immune response characterized by a time-dependent decrease in overall inflammation, increase in neutralizing antibody titer, and progressive differentiation of a broad SARS-CoV-2 CD8 T cell response. It could be desirable to aim at recapitulating the hallmarks of this robust CD8 T cell response in the design of protective COVID-19 vaccines. Disclosures Hassen Kared, PhD, ImmunoScape (Shareholder) Alessandra Nardin, DvM, ImmunoScape (Shareholder) Hermi Sumatoh, BSc, Dip MTech, ImmunoScape (Shareholder) Faris Kairi, BSc, ImmunoScape (Shareholder) Daniel Carbajo, PhD, ImmunoScape (Shareholder) Brian Abel, PhD, MBA, ImmunoScape (Shareholder) Evan Newell, PhD, ImmunoScape (Shareholder)

scholarly journals Novel Vβ specific germline contacts shape an elite controller T cell response

2020 ◽  
Author(s):  
Yang Wang ◽  
Alexandra Tsitsiklis ◽  
Wei Gao ◽  
H. Hamlet Chu ◽  
Yan Zhang ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Response ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Structural Features ◽  
T Cell Response ◽  
Elite Controller ◽  
Unusual Structure ◽  
Mhc I ◽  
Cell Responses

AbstractCertain CD8 T cell responses are particularly effective at controlling infection, as exemplified by elite control of HIV in individuals harboring HLA-B57. To understand the structural features that contribute to CD8 T cell elite control, we focused on a strongly protective CD8 T cell response directed against a parasite-derived peptide (HF10) presented by an atypical MHC-I molecule, H-2Ld. This response exhibits a focused TCR repertoire dominated by Vβ2, and a representative TCR (TG6) in complex with Ld-HF10 reveals an unusual structure in which both MHC and TCR contribute extensively to peptide specificity, along with a parallel footprint of TCR on its pMHC ligand. The parallel footprint is a common feature of Vβ2-containing TCRs and correlates with an unusual Vα-Vβ interface, CDR loop conformations, and Vβ2-specific germline contacts with peptide. Vβ2 and Ld may represent “specialist” components for antigen recognition that allow for particularly strong and focused T cell responses.

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