Support for a Possible "Vaccinal" Effect of Rituximab; Lymphoma Idiotype Specific T-Cell Responses in Follicular Lymphoma Patients Treated with Rituximab.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3424-3424
Author(s):  
Shannon P. Hilchey ◽  
Ollivier Hyrien ◽  
Richard Bankert ◽  
Daniel P. Gold ◽  
Faith Young ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Follicular Lymphoma ◽  
Mechanism Of Action ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
Independent Experiment ◽  
Cell Responses ◽  
Consistent Increase ◽  
Id Protein

Abstract Rituximab (Rtx) has shown significant therapeutic activity in follicular lymphoma (FL) patients, yet it’s exact mechanism of action has not been fully defined. Although killing of FL cells through complement dependent cytolysis, antibody dependent cellular cytotoxicity or direct induction of apoptosis may contribute to its effectiveness, these mechanisms are unlikely to be the only ones as; the clinical and molecular responses to Rtx may continue for months after the last dose and; the median duration of the second response to Rtx is longer than that of the first, findings that cannot be explained solely by the above mechanisms. Rtx induced FL cell death likely results in the release of tumor antigens in a pro-inflammatory environment which we hypothesize may provoke a cell-mediated lymphoma specific immune response. Indeed, others have suggested that such a “vaccinal” effect may be an additional mechanism of action but to our knowledge there has been no direct evidence to support this in Rtx treated patients. Methods: To provide support for this hypothesis we examined lymphoma idiotype (Id) specific T-cell responses in peripheral blood mononuclear cells (PBMC) from three patients with relapsed FL. PBMC were obtained prior to and 4–6 weeks after the last of 4 weekly doses (375mg/m2 q week) of Rtx. A lymph node biopsy was obtained prior to Rtx to generate the patient’s Id protein. Dendritic cells (DC) were generated from pre-Rtx PBMC and pulsed with; no protein (control); the patient’s Id protein (Id); or an irrelevant (Irr) protein (Id from another patient). For patient 1, pre- and post-Rtx PBMC were stimulated with the DC for 1 week, while for patients 2 and 3, PBMC were stimulated for 1 week then re-stimulated for another week with fresh DC. Effectors were then assayed in triplicate for IFN-γ producing cells by Elispot. A second independent experiment was conducted in patients 2 and 3 (ie. this study describes data from 3 patients, 5 separate experiments). Results: Pre-Rtx: There was no consistent increase in the number of Id specific or Irr protein specific T-cells as compared to that of control T-cells. Post-Rtx: Whereas there was no consistent increase in the number of Irr protein specific T-cells as compared to that of control T-cells, in all three patients (including both replicates for patients 2 and 3) there was a consistent increase in the number of Id specific T-cells as compared to that of control T-cells. When composite data from all three patients were analyzed using a mixed ANOVA, the following p-values were obtained: Comparison Pre-Rtx Post-Rtx Control vs. Id 0.03 0.0003 Id vs. Irr 0.3 0.0005 Control vs. Irr 0.2 0.9 Comparison Pre-Rtx Post-Rtx Control vs. Id 0.03 0.0003 Id vs. Irr 0.3 0.0005 Control vs. Irr 0.2 0.9 Conclusions: These data provide, to our knowledge, the first support for the hypothesis that Rtx treatment results in an increase in Id specific T-cell responses in FL patients. If indeed this is a mechanism of Rtx activity, then clinical strategies to augment this postulated vaccinal effect, such as anti-CTLA-4 antibodies or Id vaccination post Rtx, may further increase the clinical potential of this agent and change the way we develop combination therapies. Further study of immune responses in a larger number of FL patients treated with Rtx is warranted and ongoing.

scholarly journals Mycobacterium tuberculosis-Specific T Cell Functional, Memory, and Activation Profiles in QuantiFERON-Reverters Are Consistent With Controlled Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Cheleka A. M. Mpande ◽  
Pia Steigler ◽  
Tessa Lloyd ◽  
Virginie Rozot ◽  
Boitumelo Mosito ◽  
...  
Keyword(s):  
T Cells ◽  
Mycobacterium Tuberculosis ◽  
T Cell ◽  
Natural Killer ◽  
Mononuclear Cells ◽  
Γδ T Cells ◽  
T Cell Responses ◽  
Th1 Cells ◽  
Functional Responses ◽  
Cell Responses

Reversion of immune sensitization tests for Mycobacterium tuberculosis (M.tb) infection, such as interferon-gamma release assays or tuberculin skin test, has been reported in multiple studies. We hypothesized that QuantiFERON-TB Gold (QFT) reversion is associated with a decline of M.tb-specific functional T cell responses, and a distinct pattern of T cell and innate responses compared to persistent QFT+ and QFT- individuals. We compared groups of healthy adolescents (n=~30 each), defined by four, 6-monthly QFT tests: reverters (QFT+/+/-/-), non-converters (QFT-/-/-/-) and persistent positives (QFT+/+/+/+). We stimulated peripheral blood mononuclear cells with M.tb antigens (M.tb lysate; CFP-10/ESAT-6 and EspC/EspF/Rv2348 peptide pools) and measured M.tb-specific adaptive T cell memory, activation, and functional profiles; as well as functional innate (monocytes, natural killer cells), donor-unrestricted T cells (DURT: γδ T cells, mucosal-associated invariant T and natural killer T-like cells) and B cells by flow cytometry. Projection to latent space discriminant analysis was applied to determine features that best distinguished between QFT reverters, non-converters and persistent positives. No longitudinal changes in immune responses to M.tb were observed upon QFT reversion. M.tb-specific Th1 responses detected in reverters were of intermediate magnitude, higher than responses in QFT non-converters and lower than responses in persistent positives. About one third of reverters had a robust response to CFP-10/ESAT-6. Among those with measurable responses, lower proportions of TSCM (CD45RA+CCR7+CD27+) and early differentiated (CD45RA-) IFN-γ-TNF+IL-2- M.tb lysate-specific CD4+ cells were observed in reverters compared with non-converters. Conversely, higher proportions of early differentiated and lower proportions of effector (CD45RA-CCR7-) CFP10/ESAT6-specific Th1 cells were observed in reverters compared to persistent-positives. No differences in M.tb-specific innate, DURT or B cell functional responses were observed between the groups. Statistical modelling misclassified the majority of reverters as non-converters more frequently than they were correctly classified as reverters or misclassified as persistent positives. These findings suggest that QFT reversion occurs in a heterogeneous group of individuals with low M.tb-specific T cell responses. In some individuals QFT reversion may result from assay variability, while in others the magnitude and differentiation status of M.tb-specific Th1 cells are consistent with well-controlled M.tb infection.

scholarly journals Convergent epitope-specific T cell responses after SARS-CoV-2 infection and vaccination

2021 ◽  
Author(s):  
Anastasia A Minervina ◽  
Mikhail V Pogorelyy ◽  
Allison M Kirk ◽  
Emma Kaitlynn Allen ◽  
Kim J Allison ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
T Cell Response ◽  
Critical Parameters ◽  
T Cell Memory ◽  
Cell Memory ◽  
Cell Responses ◽  
Depth Analysis

SARS-CoV-2 mRNA vaccines, including Pfizer/Biontech BNT162b2, were shown to be effective for COVID-19 prevention, eliciting both robust antibody responses in naive individuals and boosting pre-existing antibody levels in SARS-CoV-2-recovered individuals. However, the magnitude, repertoire, and phenotype of epitope-specific T cell responses to this vaccine, and the effect of vaccination on pre-existing T cell memory in SARS-CoV-2 convalescent patients, are still poorly understood. Thus, in this study we compared epitope-specific T cells elicited after natural SARS-CoV-2 infection, and vaccination of both naive and recovered individuals. We collected peripheral blood mononuclear cells before and after BNT162b2 vaccination and used pools of 18 DNA-barcoded MHC-class I multimers, combined with scRNAseq and scTCRseq, to characterize T cell responses to several immunodominant epitopes, including a spike-derived epitope cross-reactive to common cold coronaviruses. Comparing responses after infection or vaccination, we found that T cells responding to spike-derived epitopes show similar magnitudes of response, memory phenotypes, TCR repertoire diversity, and αβTCR sequence motifs, demonstrating the potency of this vaccination platform. Importantly, in COVID-19-recovered individuals receiving the vaccine, pre-existing spike-specific memory cells showed both clonal expansion and a phenotypic shift towards more differentiated CCR7-CD45RA+ effector cells. In-depth analysis of T cell receptor repertoires demonstrates that both vaccination and infection elicit largely identical repertoires as measured by dominant TCR motifs and receptor breadth, indicating that BNT162b2 vaccination largely recapitulates T cell generation by infection for all critical parameters. Thus, BNT162b2 vaccination elicits potent spike-specific T cell responses in naive individuals and also triggers the recall T cell response in previously infected individuals, further boosting spike-specific responses but altering their differentiation state. Overall, our study demonstrates the potential of mRNA vaccines to induce, maintain, and shape T cell memory through vaccination and revaccination.

Human Autologous Tumor-Specific T-Cell Responses Induced by Liposome Encapsulated Lymphoma Membrane Proteins.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 749-749 ◽  
Author(s):  
Sattva S. Neelapu ◽  
Barry L. Gause ◽  
Linda Harvey ◽  
Andrea R. Frye ◽  
Jessie Horton ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Membrane Proteins ◽  
Tumor Cells ◽  
T Cell Responses ◽  
Phase Iii ◽  
Autologous Tumor ◽  
Vaccine Formulation ◽  
Cell Responses ◽  
Id Protein

Abstract The unique antigenic determinants (Idiotype [Id]) of the immunoglobulin expressed on a given B cell malignancy can serve as a tumor-specific antigen for active immunotherapy. We have previously demonstrated that Id vaccines in follicular lymphoma (FL) patients administered in the minimal residual disease (MRD) state are immunogenic and are associated with induction of complete molecular remissions and long-term disease-free survival (Nature Med 5:1171–1177, 1999). This hybridoma-derived vaccine is now being tested in a pivotal Phase III clinical trial. However, the production of Id protein by hybridoma technology for such vaccine formulation is an expensive and laborious process requiring an average of 3 to 6 months to manufacture the vaccine for each patient. To overcome this difficulty, we developed a novel vaccine formulation where we directly extracted the membrane proteins from lymph node biopsy-derived tumor cells and incorporated them into liposomes along with IL-2. Testing in preclinical studies showed this formulation to be as potent as our prototype hybridoma-derived Id protein vaccine. In the present study, 11 previously untreated and/or relapsed FL patients received 5 injections of this novel vaccine formulation subcutaneously and/or intratumorally at approximately monthly intervals. The vaccine was well tolerated and induced only minor local reactions at the sites of injection. T cell responses were evaluated by cytokine induction and IFNg ELISPOT against autologous tumor. Post-vaccine, but not pre-vaccine, peripheral blood mononuclear cells (PBMC) from 6 out of 10 patients that were assessed, recognized autologous tumor cells, as demonstrated by TNFa, GM-CSF and/or IFNg production. Significant production of cytokines was observed only in response to autologous tumor cells, but not normal B cells. The precursor frequency of tumor-reactive T cells was significantly increased in postvaccine PBMC (range 19–115 IFNg spots/100,000 PBMC), compared with prevaccine PBMC (range 2–7 IFNg spots/100,000 PBMC). Anti-MHC Class I and Class II antibodies inhibited cytokine production suggesting that both CD4+ and CD8+ T cells were involved in the anti-tumor immune responses. Vaccination was associated with induction of a sustained complete response in one patient and correlated with the generation of a potent anti-tumor T cell response. The remaining 10 patients progressed after a median duration of 8 months. We conclude that liposomal delivery of lymphoma membrane proteins is safe, induces tumor-specific CD4+ and CD8+ T cell responses, and may serve as a model for vaccine development against other human cancers. The induction of clinical response warrants further testing of this novel formulation in the setting of MRD where the immunosuppressive effects of the tumor are likely to be least.

Sipuleucel-T (sip-T) induced lytic CD8+ T cell responses to target antigens in men with hormone-sensitive and castration-resistant prostate cancer (CRPC).

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 162-162
Author(s):  
Emmanuel S. Antonarakis ◽  
David I. Quinn ◽  
Adam S. Kibel ◽  
Daniel Peter Petrylak ◽  
Tuyen Vu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
Cell Responses ◽  
Hormone Sensitive ◽  
Ctl Activity

162 Background: Sip-T is an FDA-approved immunotherapy for patients (pts) with asymptomatic or minimally symptomatic metastatic CRPC. Sip-T is manufactured from autologous peripheral blood mononuclear cells cultured with the immunogen PA2024, a fusion antigen of prostatic acid phosphatase (PAP) conjugated to granulocyte macrophage colony-stimulating factor. After sip-T, antibody and T cell responses to PA2024 and/or PAP correlate with improved survival. To further elucidate the mechanism of sip-T–induced immune responses, we evaluated the proliferative and lytic ability of PA2024- and PAP-specific CD8+ T cells. Methods: Mononuclear blood cells were labeled with the membrane dye carboxyfluorescein succinimidyl ester (CFSE) and cultured with PA2024 or PAP. In vitro proliferative and lytic CD8+ (cytotoxic T lymphocyte [CTL]) T cell responses to these antigens were evaluated by flow cytometry. For proliferation, progressive dilution of CFSE was measured. For CTL activity, the loss of intracellular granzyme B (GzB), indicating exocytosis of this apoptosis-mediating enzyme, was assessed. Samples were from 2 sip-T clinical trials STAND (NCT01431391) and STRIDE (NCT01981122), hormone-sensitive and CRPC pts, respectively. Results: Six wk after sip-T administration, CD8+ PAP- and PA2024-specific responses were observed (n=14 pts assessed). The magnitude of PA2024-specific CD8+ proliferative responses was greater than that for PAP-specific responses. CD8+ T cells from a subset of pts who exhibited PA2024- and/or PAP-specific proliferative responses were assessed for lytic ability. After in vitro antigen stimulation, CTL activity in all evaluated samples (n=14, PA2024; n=13, PAP) was demonstrated by a significant decrease (p<0.05) in intracellular GzB relative to a no-antigen control. Conclusions: Sip-T induced CD8+ CTL proliferation against the target antigens PAP and PA2024. Moreover, antigen-specific CTL activity provides the first direct evidence that sip-T can induce tumor cell lysis. These antigen-specific CD8+ lytic abilities were observed within 6 wk following sip-T, suggesting rapidly generated immune responses. Clinical trial information: NCT01431391; NCT01981122.

scholarly journals Inactivated Simian Immunodeficiency Virus-Pulsed Autologous Fresh Blood Cells as an Immunotherapy Strategy

2008 ◽  
Vol 83 (3) ◽  
pp. 1501-1510 ◽  
Author(s):  
Rosemarie D. Mason ◽  
Sheilajen Alcantara ◽  
Viv Peut ◽  
Liyen Loh ◽  
Jeffrey D. Lifson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Simian Immunodeficiency Virus ◽  
Blood Cells ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
T Cell Epitopes ◽  
Peripheral Blood Mononuclear ◽  
Cell Responses ◽  
Immunodeficiency Virus

ABSTRACT Practical immunotherapies for human immunodeficiency virus infection are needed. We evaluated inactivated simian immunodeficiency virus (SIV) pulsed onto fresh peripheral blood mononuclear cells in 12 pigtail macaques with chronic SIVmac251 infection for T-cell immunogenicity in a randomized cross-over design study. The immunotherapy was safe and convincingly induced high levels of SIV-specific CD4+ T-cell responses (mean, 5.9% ± 1.3% of all CD4+ T cells) and to a lesser extent SIV-specific CD8+ T-cell responses (mean, 0.7% ± 0.4%). Responses were primarily directed toward Gag and less frequently toward Env but not Pol or regulatory/accessory SIV proteins. T-cell responses against Gag were generally broad and polyfunctional, with a mean of 2.7 CD4+ T-cell epitopes mapped per animal and more than half of the SIV Gag-specific CD4+ T cells expressing three or more effector molecules. The immunogenicity was comparable to that found in previous studies of peptide-pulsed blood cells. Despite the high-level immunogenicity, no reduction in viral load was observed in the chronically viremic macaques. This contrasts with our studies of immunization with peptide-pulsed blood cells during early SIV infection in macaques. Future studies of inactivated virus-pulsed blood cell immunotherapy during early infection of patients receiving antiretroviral therapy are warranted.

scholarly journals Safety and exceptional immunogenicity of novel 5T4 viral vectored vaccination regimes in early stage prostate cancer: a phase I clinical trial

2020 ◽  
Author(s):  
Federica Cappuccini ◽  
Richard Bryant ◽  
Emily Pollock ◽  
Lucy Carter ◽  
Clare Verrill ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Early Stage ◽  
Specific Antigen ◽  
T Cell Responses ◽  
Cell Responses ◽  
Cell Immunity

AbstractProstate cancer (PCa) has been under investigation as a target for antigen-specific immunotherapies in metastatic disease settings for a decade. However, neither of the two clinically most developed prostate cancer vaccines, Sipuleucel-T and ProstVac, induce strong T cell immunity. In this first-in-man study, VANCE, we evaluated a novel vaccination platform based on two replication-deficient viruses, chimpanzee adenovirus (ChAd) and MVA (Modified Vaccinia Ankara), targeting the oncofetal self-antigen 5T4 in early stage PCa. Forty patients, either newly diagnosed with early stage prostate cancer and scheduled for radical prostatectomy or patients with stable disease on an active surveillance protocol, were recruited to the study to assess the vaccine safety and T cell immunogenicity. Secondary and exploratory endpoints included immune infiltration into the prostate, prostate specific antigen (PSA) change and assessment of phenotype and functionality of antigen-specific T cells. The vaccine had an excellent safety profile. Vaccination-induced 5T4-specific T cell responses were measured in blood by ex vivo IFN-γ ELISpot and were detected in the majority of patients with a mean level in responders of 198 spot-forming cells (SFC) per million peripheral blood mononuclear cells (PBMCs). Flow cytometry analysis demonstrated the presence of both CD8+ and CD4+ polyfunctional 5T4-specific T cells in the circulation. 5T4-reactive tumour infiltrating lymphocytes (TILs) were isolated from post-treatment prostate tissue. Some of the patients had a transient PSA rise 2-8 weeks following vaccination, possibly indicating an inflammatory response in the target organ. The potent T cell responses elicited support the evaluation of these vectored vaccine in efficacy trials.

scholarly journals Human CLEC9A antibodies deliver NY-ESO-1 antigen to CD141+ dendritic cells to activate naïve and memory NY-ESO-1-specific CD8+ T cells

2020 ◽  
Vol 8 (2) ◽  
pp. e000691 ◽  
Author(s):  
Kelly-Anne Masterman ◽  
Oscar L Haigh ◽  
Kirsteen M Tullett ◽  
Ingrid M Leal-Rojas ◽  
Carina Walpole ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Effector Function ◽  
Immunogenic Tumor ◽  
Cross Presentation ◽  
Cell Responses

BackgroundDendritic cells (DCs) are crucial for the efficacy of cancer vaccines, but current vaccines do not harness the key cDC1 subtype required for effective CD8+ T-cell-mediated tumor immune responses. Vaccine immunogenicity could be enhanced by specific delivery of immunogenic tumor antigens to CD141+ DCs, the human cDC1 equivalent. CD141+ DCs exclusively express the C-type-lectin-like receptor CLEC9A, which is important for the regulation of CD8+ T cell responses. This study developed a new vaccine that harnesses a human anti-CLEC9A antibody to specifically deliver the immunogenic tumor antigen, NY-ESO-1 (New York esophageal squamous cell carcinoma 1), to human CD141+ DCs. The ability of the CLEC9A-NY-ESO-1 antibody to activate NY-ESO-1-specific naïve and memory CD8+ T cells was examined and compared with a vaccine comprised of a human DEC-205-NY-ESO-1 antibody that targets all human DCs.MethodsHuman anti-CLEC9A, anti-DEC-205 and isotype control IgG4 antibodies were genetically fused to NY-ESO-1 polypeptide. Cross-presentation to NY-ESO-1-epitope-specific CD8+ T cells and reactivity of T cell responses in patients with melanoma were assessed by interferon γ (IFNγ) production following incubation of CD141+ DCs and patient peripheral blood mononuclear cells with targeting antibodies. Humanized mice containing human DC subsets and a repertoire of naïve NY-ESO-1-specific CD8+ T cells were used to investigate naïve T cell priming. T cell effector function was measured by expression of IFNγ, MIP-1β, tumor necrosis factor and CD107a and by lysis of target tumor cells.ResultsCLEC9A-NY-ESO-1 antibodies (Abs) were effective at mediating delivery and cross-presentation of multiple NY-ESO-1 epitopes by CD141+ DCs for activation of NY-ESO-1-specific CD8+ T cells. When benchmarked to NY-ESO-1 conjugated to an untargeted control antibody or to anti-human DEC-205, CLEC9A-NY-ESO-1 was superior at ex vivo reactivation of NY-ESO-1-specific T cell responses in patients with melanoma. Moreover, CLEC9A-NY-ESO-1 induced priming of naïve NY-ESO-1-specific CD8+ T cells with polyclonal effector function and potent tumor killing capacity in vitro.ConclusionsThese data advocate human CLEC9A-NY-ESO-1 Ab as an attractive strategy for specific targeting of CD141+ DCs to enhance tumor immunogenicity in NY-ESO-1-expressing malignancies.

scholarly journals Comparison of Human Immunodeficiency Virus (HIV)-Specific T-Cell Responses in HIV-1- and HIV-2-Infected Individuals in Senegal

2004 ◽  
Vol 78 (24) ◽  
pp. 13934-13942 ◽  
Author(s):  
N. N. Zheng ◽  
N. B. Kiviat ◽  
P. S. Sow ◽  
S. E. Hawes ◽  
A. Wilson ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
T Helper ◽  
Cell Responses ◽  
Cell Immunity ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 2 (HIV-2) infection is typically less virulent than HIV-1 infection, which may permit the host to mount more effective, sustained T-cell immunity. We investigated antiviral gamma interferon-secreting T-cell responses by an ex vivo Elispot assay in 68 HIV-1- and 55 HIV-2-infected Senegalese patients to determine if differences relate to more efficient HIV-2 control. Homologous HIV-specific T cells were detected in similar frequencies (79% versus 76%, P = 0.7) and magnitude (3.12 versus 3.08 log10 spot-forming cells/106 peripheral blood mononuclear cells) in HIV-1 and HIV-2 infection, respectively. Gag-specific responses predominated in both groups (≥64%), and significantly higher Nef-specific responses occurred in HIV-1-infected (54%) than HIV-2-infected patients (22%) (P < 0.001). Heterologous responses were more frequent in HIV-1 than in HIV-2 infection (46% versus 27%, P = 0.04), but the mean magnitude was similar. Total frequencies of HIV-specific responses in both groups did not correlate with plasma viral load and CD4+ T-cell count in multivariate regression analyses. However, the magnitude of HIV-2 Gag-specific responses was significantly associated with lower plasma viremia in HIV-1-infected patients (P = 0.04). CD4+ T-helper responses, primarily recognizing HIV-2 Gag, were detected in 48% of HIV-2-infected compared to only 8% of HIV-1-infected patients. These findings indicate that improved control of HIV-2 infection may relate to the contribution of T-helper cell responses. By contrast, the superior control of HIV-1 replication associated with HIV-2 Gag responses suggests that these may represent cross-reactive, higher-avidity T cells targeting epitopes within Gag regions of functional importance in HIV replication.

scholarly journals Evaluation of Antigen-Specific T-Cell Responses with a Miniaturized and Automated Method

2008 ◽  
Vol 15 (12) ◽  
pp. 1811-1818 ◽  
Author(s):  
Giuseppina Li Pira ◽  
Federico Ivaldi ◽  
Chiara Dentone ◽  
Elda Righi ◽  
Valerio Del Bono ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Peripheral Blood Mononuclear ◽  
Cell Responses ◽  
Automated Method ◽  
Cell Immunity

ABSTRACT The evaluation of antigen-specific T-cell responses is helpful for both research and clinical settings. Several techniques can enumerate antigen-responsive T cells or measure their products, but they require remarkable amounts of peripheral blood mononuclear cells (PBMCs). Since screening numerous antigens or testing samples from pediatric or lymphopenic patients is hampered in clinical practice, we refined a miniaturized, high-throughput assay for T-cell immunity. Antigens and cells in 10-μl volumes were dispensed into 1,536-well culture plates precoated with anti-gamma interferon (anti-IFN-γ) antibodies. After being cultured, the wells were developed by enzyme-linked immunosorbent assay for bound cytokine. Miniaturization and automation allowed quantitation of antigen-specific responses on 104 PBMCs. This method was applied for epitope mapping of mycobacterial antigens and was used in the clinic to evaluate T-cell immunity to relevant opportunistic pathogens by using small blood samples. A comparison with conventional methods showed similar sensitivity. Therefore, current flow cytometric methods that provide information on frequency and phenotype of specific T cells can be complemented by this assay that provides extensive information on cytokine concentrations and profiles and requires 20- to 50-fold fewer PBMCs than other analytical methods.

scholarly journals Selection and T-cell antigenicity of synthetic long peptides derived from SARS-CoV-2

2022 ◽  
Vol 103 (1) ◽  
Author(s):  
Katarzyna Piadel ◽  
Amin Haybatollahi ◽  
Angus George Dalgleish ◽  
Peter Lawrence Smith
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
Hla Class I ◽  
Peripheral Blood Mononuclear ◽  
Cell Responses

The pandemic caused by SARS-CoV-2 has led to the successful development of effective vaccines however the prospect of variants of SARS-CoV-2 and future coronavirus outbreaks necessitates the investigation of other vaccine strategies capable of broadening vaccine mediated T-cell responses and potentially providing cross-immunity. In this study the SARS-CoV-2 proteome was assessed for clusters of immunogenic epitopes restricted to diverse human leucocyte antigen. These regions were then assessed for their conservation amongst other coronaviruses representative of different alpha and beta coronavirus genera. Sixteen highly conserved peptides containing numerous HLA class I and II restricted epitopes were synthesized from these regions and assessed in vitro for their antigenicity against T-cells from individuals with previous SARS-CoV-2 infection. Monocyte derived dendritic cells were generated from these peripheral blood mononuclear cells (PBMC), loaded with SARS-CoV-2 peptides, and used to induce autologous CD4+ and CD8+ T cell activation. The SARS-CoV-2 peptides demonstrated antigenicity against the T-cells from individuals with previous SARS-CoV-2 infection indicating that this approach holds promise as a method to activate anti-SAR-CoV-2 T-cell responses from conserved regions of the virus which are not included in vaccines utilising the Spike protein.

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