scholarly journals Presence of SARS-CoV-2-reactive T cells in COVID-19 patients and healthy donors

2020 ◽  
Author(s):  
Julian Braun ◽  
Lucie Loyal ◽  
Marco Frentsch ◽  
Daniel Wendisch ◽  
Philipp Georg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Transmembrane Domain ◽  
Clinical Manifestations ◽  
T Cell Responses ◽  
Spike Glycoprotein ◽  
Cell Responses ◽  
Healthy Donors

SummarySevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a rapidly unfolding pandemic, overwhelming health care systems worldwide1. Clinical manifestations of Coronavirus-disease 2019 (COVID-19) vary broadly, ranging from asymptomatic infection to acute respiratory failure and death2, yet the underlying mechanisms for this high variability are still unknown. Similarly, the role of host immune responses in viral clearance of COVID-19 remains unresolved. For SARS-CoV (2002/03), however, it has been reported that CD4+ T cell responses correlated with positive outcomes3,4, whereas T cell immune responses to SARS-CoV-2 have not yet been characterized. Here, we describe an assay that allows direct detection and characterization of SARS-CoV-2 spike glycoprotein (S)-reactive CD4+ T cells in peripheral blood. We demonstrate the presence of S-reactive CD4+ T cells in 83% of COVID-19 patients, as well as in 34% of SARS-CoV-2 seronegative healthy donors (HD), albeit at lower frequencies. Strikingly, S-reactive CD4+ T cells in COVID-19 patients equally targeted N-terminal and C-terminal epitopes of S whereas in HD S-reactive CD4+ T cells reacted almost exclusively to the C-terminal epitopes that are a) characterized by higher homology with spike glycoprotein of human endemic “common cold” coronaviruses (hCoVs), and b) contains the S2 subunit of S with the cytoplasmic peptide (CP), the fusion peptide (FP), and the transmembrane domain (TM) but not the receptor-binding domain (RBD). In contrast to S-reactive CD4+ T cells in HD, S-reactive CD4+ T cells from COVID-19 patients co-expressed CD38 and HLA-DR, indivative of their recent in vivo activation. Our study is the first to directly measure SARS-CoV-2-reactive T cell responses providing critical tools for large scale testing and characterization of potential cross-reactive cellular immunity to SARS-CoV-2. The presence of pre-existing SARS-CoV-2-reactive T cells in a subset of SARS-CoV-2 naïve HD is of high interest but larger scale prospective cohort studies are needed to assess whether their presence is a correlate of protection or pathology for COVID-19. Results of such studies will be key for a mechanistic understanding of the SARS-CoV-2 pandemic, adaptation of containment methods and to support vaccine development.

scholarly journals Functional analysis of peripheral and intratumoral neoantigen-specific TCRs identified in a patient with melanoma

2021 ◽  
Vol 9 (9) ◽  
pp. e002754
Author(s):  
Eva Bräunlein ◽  
Gaia Lupoli ◽  
Franziska Füchsl ◽  
Esam T Abualrous ◽  
Niklas de Andrade Krätzig ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Immune Checkpoint ◽  
T Cell Responses ◽  
Functional Avidity ◽  
Cell Responses

BackgroundNeoantigens derived from somatic mutations correlate with therapeutic responses mediated by treatment with immune checkpoint inhibitors. Neoantigens are therefore highly attractive targets for the development of therapeutic approaches in personalized medicine, although many aspects of their quality and associated immune responses are not yet well understood. In a case study of metastatic malignant melanoma, we aimed to perform an in-depth characterization of neoantigens and respective T-cell responses in the context of immune checkpoint modulation.MethodsThree neoantigens, which we identified either by immunopeptidomics or in silico prediction, were investigated using binding affinity analyses and structural simulations. We isolated seven T-cell receptors (TCRs) from the patient’s immune repertoire recognizing these antigens. TCRs were compared in vitro by multiparametric analyses including functional avidity, multicytokine secretion, and cross-reactivity screenings. A xenograft mouse model served to study in vivo functionality of selected TCRs. We investigated the patient’s TCR repertoire in blood and different tumor-related tissues over 3 years using TCR beta deep sequencing.ResultsSelected mutated peptide ligands with proven immunogenicity showed similar binding affinities to the human leukocyte antigen complex and comparable disparity to their wild-type counterparts in molecular dynamic simulations. Nevertheless, isolated TCRs recognizing these antigens demonstrated distinct patterns in functionality and frequency. TCRs with lower functional avidity showed at least equal antitumor immune responses in vivo. Moreover, they occurred at high frequencies and particularly demonstrated long-term persistence within tumor tissues, lymph nodes and various blood samples associated with a reduced activation pattern on primary in vitro stimulation.ConclusionsWe performed a so far unique fine characterization of neoantigen-specific T-cell responses revealing defined reactivity patterns of neoantigen-specific TCRs. Our data highlight qualitative differences of these TCRs associated with function and longevity of respective T cells. Such features need to be considered for further optimization of neoantigen targeting including adoptive T-cell therapies using TCR-transgenic T cells.

T Cell Responses Directed Against HLA A*0201-Restricted Epitopes Derived from WT1 Are Readily Identifiable in Patients with AML and CML, but Not in Patients with ALL.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2526-2526
Author(s):  
Katayoun Rezvani ◽  
Jason Brenchley ◽  
David Price ◽  
Yasemin Kilical ◽  
Matthias Grube ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Mhc Class I ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Healthy Donors ◽  
Myeloid Leukemias

Abstract The WT1 gene contributes to leukemogenesis and all adult ALL, AML and CML express WT1 RNA by quantitative real-time reverse transcription polymerase chain reaction (qPCR) techniques. WT1 may therefore be a useful antigenic target for immunotherapy. Four HLA-A*0201-restricted WT1 T cell epitopes have been identified: Db126 (RMFPNAPYL), WH187 (SLGEQQYSV), WT37-45 (VLDFAPPGA) and WT235 (CMTWNQMNL), but only Db126 has been extensively studied in myeloid leukemias. Here, we sought CD8+ T cells directed against these epitopes in 12 healthy SCT donors, 6 patients with AML, 8 with, CML and 6 with ALL prior to SCT. All patients tested with myeloid or lymphoid leukemias expressed MHC class I, B7.1 and WT1. To detect very low frequencies of WT1-specific CD8+ T cells, we used qPCR for interferon-g (IFN-g) mRNA. After isolation, 106 CD8+ T cells were stimulated with C1R-A2 cells (MHC class I-defective LCL cells transfected with HLA-A*0201) loaded with test peptides at concentrations of 0.1, 1 and 10 mM to determine their functional avidity. CD8+ T cells were also stimulated with CMV pp65 (positive control) and gp100 (209-2M) (negative control) peptides. After 3 hr coculture, cells were harvested for RNA extraction and cDNA synthesis. qPCR was performed for IFN-g mRNA and normalized to copies of CD8 mRNA from the same sample. Parallel assays using tetramers demonstrated that the IFN-g copy number was linearly related to the frequency of tetramer-binding T cells, sensitive to frequencies of 1 responding CD8+ T cell/100 000 CD8+ T cells. A positive response was defined as a threshold of 100 or more IFN-g mRNA copies/104 CD8 copies and a stimulation index (SI) of 2 or more, where SI = IFN-g mRNA copies/104 CD8 copies in peptide pulsed/unpulsed cultures. Responses to at least one WT1 peptide were detected in 5/8 CML patients, 4/6 patients with AML and 7/12 healthy donors. Notably, a response was not elicited to WT1 in any of the 6 patients with ALL, despite evidence of immune competence as shown by a normal CMV response. Five of five CML responders and 3/4 AML responders recognized 2 or more WT1 epitopes, while the 7 healthy donors recognized only one WT1 epitope. The range of IFN-g mRNA copies/104 CD8 copies was 289–13584, 418–45891 and 160–2683 for CML, AML and healthy donors respectively. WT1-specific tetramer-positive CD8+ T cells displayed both central memory (CD45RO+CD27+CD57−) and terminally differentiated effector memory phenotypes (CD45RO-CD27−CD57+). As multiple WT1-derived epitopes can be targeted simultaneously, it is likely that T cell response to WT1 is polyclonal. These results are important because the presence of memory WT1 responses in patients with myeloid leukemias and healthy individuals should favor vaccination as a means to expand immune responses to leukemia in the autologous and allogeneic transplant setting. Furthermore, the presence of CD8+ T cell responses to multiple WT1 epitopes should favor robust polyclonal immune responses to leukemia. However, failure to detect CD8+ T cell responses to WT1 in ALL patients suggests that WT1 may not be a useful antigen to target for immunotherapeutic purposes in this patient group.

scholarly journals Melioidosis Patient Survival Correlates With Strong IFN-γ Secreting T Cell Responses Against Hcp1 and TssM

2021 ◽  
Vol 12 ◽  
Author(s):  
Sineenart Sengyee ◽  
Atchara Yarasai ◽  
Rachan Janon ◽  
Chumpol Morakot ◽  
Orawan Ottiwet ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Clinical Manifestations ◽  
T Cell Responses ◽  
Peptide Pool ◽  
Humoral Immune ◽  
Cell Responses ◽  
Humoral Immune Responses ◽  
Healthy Donors ◽  
Ifn Γ

Melioidosis, caused by the Gram-negative bacterium Burkholderia pseudomallei, is a serious infectious disease with diverse clinical manifestations. The morbidity and mortality of melioidosis is high in Southeast Asia and no licensed vaccines currently exist. This study was aimed at evaluating human cellular and humoral immune responses in Thai adults against four melioidosis vaccine candidate antigens. Blood samples from 91 melioidosis patients and 100 healthy donors from northeast Thailand were examined for immune responses against B. pseudomallei Hcp1, AhpC, TssM and LolC using a variety of cellular and humoral immune assays including IFN-γ ELISpot assays, flow cytometry and ELISA. PHA and a CPI peptide pool were also used as control stimuli in the ELISpot assays. Hcp1 and TssM stimulated strong IFN-γ secreting T cell responses in acute melioidosis patients which correlated with survival. High IFN-γ secreting CD4+ T cell responses were observed during acute melioidosis. Interestingly, while T cell responses of melioidosis patients against the CPI peptide pool were low at the time of enrollment, the levels increased to the same as in healthy donors by day 28. Although high IgG levels against Hcp1 and AhpC were detected in acute melioidosis patients, no significant differences between survivors and non-survivors were observed. Collectively, these studies help to further our understanding of immunity against disease following natural exposure of humans to B. pseudomallei as well as provide important insights for the selection of candidate antigens for use in the development of safe and effective melioidosis subunit vaccines.

Immunologically Targeting the Leukaemia Phosphoproteome

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1016-1016
Author(s):  
Hugo De La Peña ◽  
Thomas Butler ◽  
Hsing-Wen Huang ◽  
Toral Jakhira ◽  
Chung-Yang Joseph ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Primary Tumour ◽  
T Cell Responses ◽  
Class I ◽  
Central Tolerance ◽  
Mhc Molecules ◽  
Cell Responses ◽  
Healthy Donors

Abstract Abstract 1016 Posttranslationally modified (PTM) antigens, particularly phosphorylated antigens, comprise a significant component of tumour antigens and are thought to be represented within anti-tumour immune responses. Moreover, PTM antigens may circumvent the barrier of central tolerance thus offer a new paradigm for immunologically targeting malignant disease. Our previous work has shown that altered signal transduction in neoplastic myeloid and lymphoid cells can generate novel phosphopeptides that are uniquely and differentially presented on malignant cells by class I MHC molecules. Here, we have examined the peripheral blood CD8+ and CD4+ T cell immune responses against phosphopeptide antigens, displayed on primary haematolymphoid malignancies, in healthy donors and patients with leukaemia. Using HLA class-I and class-II tetramers in addition to cytotoxicity assays, we have found that these T cell responses are highly cytotoxic in both in vitro and in vivo preclinical models of adoptive immunotherapy. Our data suggest that recall responses are present to a significant proportion of previously identified class-I restricted phosphorylated antigens in healthy donors. Furthermore, in ex-vivo stimulation renders T cell responses to more than 90% of phosphopeptide antigens tested. These T cells recognise and kill primary tumour cells in a phosphopeptide-specific manner. Ten out of 10 HLA A2 donors and 9 out of 10 HLA B7 donors each respond to up to 7 different phosphopeptides from our pools (50 to 100 different phosphopeptides from CLL and AML). Some of the most relevant cytotoxic CD4+ T cell responses generated are directed towards CLL-specific phosphoproteins such as phosphorylated CD19, CXCR4 and CD20 whereas some of the most relevant cytotoxic CD8+ T cell responses generated target CLL specific phosphopeptides derived from LSP1, MRCL3 and NRC1I3. All these antigens are either overexpressed or uniquely expressed on CLL primary tumour cells. High affinity, tetramer-binding T cells against phosphopeptides derived from BCL2, cMyc, GFI1, MLL transcription factor, LIM, RUNX1, SKI, GRK and MAP3K, have been successfully generated from healthy donors which elicit strong cytotoxic responses against primary tumours. No responses have been elicited to the nonphosphorylated counterparts. Furthermore, some of the phosphopeptides are uniquely displayed on primary AML tissue and derived from established leukaemogenic oncoproteins making them extremely attractive targets. These data support the hypothesis that T cells specific for PTM antigens are represented within the peripheral T cell repertoire and thus are not subject to central tolerance and can be exploited to recognise and destroy neoplastic cells. As haematolymphoid malignancies do not typically downregulate MHC molecules, T cell adoptive transfer can now be envisaged while phosphopeptide vaccination strategies are also a clear objective. Disclosures: No relevant conflicts of interest to declare.

scholarly journals 413 GEN-009, a personalized neoantigen vaccine, elicits robust immune responses in individuals with advanced or metastatic solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A438-A438
Author(s):  
Mara Shainheit ◽  
Devin Champagne ◽  
Gabriella Santone ◽  
Syukri Shukor ◽  
Ece Bicak ◽  
...  
Keyword(s):  
Clinical Trial ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Solid Tumors ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Checkpoint Blockade ◽  
T Cell Subsets ◽  
Cell Responses

BackgroundATLASTM is a cell-based bioassay that utilizes a cancer patient‘s own monocyte-derived dendritic cells and CD4+ and CD8+ T cells to screen their mutanome and identify neoantigens that elicit robust anti-tumor T cell responses, as well as, deleterious InhibigensTM.1 GEN-009, a personalized vaccine comprised of 4–20 ATLAS-identified neoantigens combined with Hiltonol®, harnesses the power of neoantigen-specific T cells to treat individuals with solid tumors. The safety and efficacy of GEN-009 is being assessed in a phase 1/2a clinical trial (NCT03633110).MethodsA cohort of 15 adults with solid tumors were enrolled in the study. During the screening period, patients received standard of care PD-1-based immunotherapies appropriate for their tumor type. Subsequently, patients were immunized with GEN-009 with additional doses administered at 3, 6, 12, and 24 weeks. Peripheral blood mononuclear cells (PBMCs) were collected at baseline, pre-vaccination (D1), as well as 29, 50, 92, and 176 days post first dose. Vaccine-induced immunogenicity and persistence were assessed by quantifying neoantigen-specific T cell responses in ex vivo and in vitro stimulation dual-analyte fluorospot assays. Polyfunctionality of neoantigen-specific T cells was evaluated by intracellular cytokine staining. Additionally, potential correlations between the ATLAS-identified profile and vaccine-induced immunogenicity were assessed.ResultsGEN-009 augmented T cell responses in 100% of evaluated patients, attributable to vaccine and not checkpoint blockade. Furthermore, neoantigen-induced secretion of IFNγ and/or TNFα by PBMCs, CD4+, and CD8+ T cells was observed in all patients. Responses were primarily from polyfunctional TEM cells and detectable in both CD4+ and CD8+ T cell subsets. Some patients had evidence of epitope spreading. Unique response patterns were observed for each patient with no apparent relationship between tumor types and time to emergence, magnitude or persistence of response. Ex vivo vaccine-induced immune responses were observed as early as 1 month, and in some cases, persisted for 176 days. Clinical efficacy possibly attributable to GEN-009 was observed in several patients, but no correlation has yet been identified with neoantigen number or magnitude of immune response.ConclusionsATLAS empirically identifies stimulatory neoantigens using the patient‘s own immune cells. GEN-009, which is comprised of personalized, ATLAS-identified neoantigens, elicits early, long-lasting and polyfunctional neoantigen-specific CD4+ and CD8+ T cell responses in individuals with advanced cancer. Several patients achieved clinical responses that were possibly attributable to vaccine; efforts are underway to explore T cell correlates of protection. These data support that GEN-009, in combination with checkpoint blockade, represents a unique approach to treat solid tumors.AcknowledgementsWe are grateful to the patients and their families who consented to participate in the GEN-009-101 clinical trial.Trial RegistrationNCT03633110Ethics ApprovalThis study was approved by Western Institutional Review Board, approval number 1-1078861-1. All subjects contributing samples provided signed individual informed consent.ReferenceDeVault V, Starobinets H, Adhikari S, Singh S, Rinaldi S, Classon B, Flechtner J, Lam H. Inhibigens, personal neoantigens that drive suppressive T cell responses, abrogate protection of therapeutic anti-tumor vaccines. J. Immunol 2020; 204(1 Supplement):91.15.

Long term results from a phase 1 trial of GEN-009, a personalized neoantigen vaccine, combined with PD-1 inhibition in advanced solid tumors.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2613-2613
Author(s):  
Maura L. Gillison ◽  
Mark M. Awad ◽  
Przemyslaw Twardowski ◽  
Ammar Sukari ◽  
Melissa Lynne Johnson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Solid Tumors ◽  
Salvage Therapy ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Long Term Results ◽  
Advanced Solid Tumors ◽  
Cell Responses

2613 Background: GEN-009 is an adjuvanted personalized cancer vaccine containing up to 20 neoantigens selected by ATLAS, an ex vivo bioassay screening autologous T cells for immune responses against both neoantigens as well as Inhibigens. Inhibigen-specific T cells suppress immunity and have been shown to accelerate tumor progression in mice and are avoided in GEN-009. In cohort A, all patients immunized in the adjuvant setting with GEN-009 monotherapy developed immune responses. Nearly all (99%) of selected peptides were immunogenic: ex vivo CD4+ and CD8+ fluorospot responses specific for 51% and 41% of immunized peptides, respectively. Seven of 8 patients continue without progression with a median follow up of 18 months. Methods: GEN-009 is being evaluated in patients (pts) with advanced cancer who received standard-of-care (SOC) PD-1 inhibitor as monotherapy or in combination therapy during vaccine manufacturing. Five vaccine doses were administered over 24 weeks in combination with a PD-1 CPI. Patients who progressed prior to vaccination received alternative salvage therapy followed by GEN-009 in combination. Peripheral T cell responses were measured by fluorospot assays in ex vivo and in vitro stimulation. Results: 15 pts received GEN-009 in combination with a PD-1 inhibitor; 1 patient received GEN-009 monotherapy. Median number of neoantigens per vaccine was 14 (5-18). GEN-009-related adverse events were limited to vaccine injection site reactions and mild myalgias or fatigue. Longitudinal evaluation of ex vivo T cell responses revealed that sequential vaccination with GEN-009 had an overall additive effect on the robustness of IFNγ secretion and responses were persistent for at least 6 months in some patients. Epitope spread was detected in CPI sensitive patients, but not in CPI refractory patients receiving salvage therapy. Three patients who responded to PD-1 inhibition followed by disease stabilization then demonstrated further reduction after GEN-009 vaccination that could represent vaccine effect. Eight of 9 CPI responsive patients are progression-free from 3 to 10 months after first vaccine dose. Four of 7 CPI refractory patients have experienced unexpected prolonged stable disease after vaccination of up to 8 months after vaccination. 2 of 2 patients with available samples lost all evidence of circulating tumor DNA including non-targeted neoantigens. Conclusions: Vaccination with GEN-009 in combination with anti-PD-1 CPI in patients with advanced solid tumors shows little additive toxicity. Preliminary data demonstrate induction of broad neoantigen-specific immune responses and epitope spreading in the presence of PD-1 CPI. Broad immunity against tumor specific targets and encouraging patient outcomes support further study. Clinical trial information: NCT03633110.

scholarly journals Baseline Levels of Influenza-Specific B Cells and T Cell Responses Modulate Human Immune Responses to Swine Variant Influenza A/H3N2 Vaccine

Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 126
Author(s):  
Lilin Lai ◽  
Nadine Rouphael ◽  
Yongxian Xu ◽  
Amy C. Sherman ◽  
Srilatha Edupuganti ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Influenza A ◽  
Vaccine Dose ◽  
T Cell Responses ◽  
Post Vaccination ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Cellular Immune

The cellular immune responses elicited by an investigational vaccine against an emergent variant of influenza (H3N2v) are not fully understood. Twenty-five subjects, enrolled in an investigational influenza A/H3N2v vaccine study, who received two doses of vaccine 21 days apart, were included in a sub-study of cellular immune responses. H3N2v-specific plasmablasts were determined by ELISpot 8 days after each vaccine dose and H3N2v specific CD4+ T cells were quantified by intracellular cytokine and CD154 (CD40 ligand) staining before vaccination, 8 and 21 days after each vaccine dose. Results: 95% (19/20) and 96% (24/25) subjects had pre-existing H3N2v specific memory B, and T cell responses, respectively. Plasmablast responses at Day 8 after the first vaccine administration were detected against contemporary H3N2 strains and correlated with hemagglutination inhibition HAI (IgG: p = 0.018; IgA: p < 0.001) and Neut (IgG: p = 0.038; IgA: p = 0.021) titers and with memory B cell frequency at baseline (IgA: r = 0.76, p < 0.001; IgG: r = 0.74, p = 0.0001). The CD4+ T cells at Days 8 and 21 expanded after prime vaccination and this expansion correlated strongly with early post-vaccination HAI and Neut titers (p ≤ 0.002). In an adult population, the rapid serological response observed after initial H3N2v vaccination correlates with post-vaccination plasmablasts and CD4+ T cell responses.

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.

Co-Existing Serological Immune Responses against RHAMM Might Be a Prerequisite for Strong Cellular Immune Responses of CD8-Positive T Cells in RHAMM-R3 Peptide Vaccination for Patients with Different Hematological Malignancies.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3671-3671
Author(s):  
Jochen Greiner ◽  
Susanne Hofmann ◽  
Krzysztof Giannopoulos ◽  
Markus Rojewski ◽  
Anna Babiak ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
High Dose ◽  
Clinical Effects ◽  
Peptide Vaccination ◽  
Cell Responses ◽  
Tetramer Staining

Abstract Abstract 3671 Poster Board III-607 For effective elimination of malignant cells by specific T cells a co-activation of CD4- and CD8-positive T cells might be important. We performed two RHAMM-R3 peptide vaccination trials using 300μg and 1000μg for patients with AML, MDS and multiple myeloma overexpressing RHAMM. Similar mild toxicity of both cohorts was found, only mild drug-related adverse events were observed such as erythema and induration of the skin. In the 300μg cohort we detected in 7/10 (70 %) patients specific immune responses and also positive clinical effects in 5/10 (50 %) patients. In the high dose peptide vaccination trial (1000μg peptide) 4/9 (44 %) patients showed positive immune responses. These patients showed an increase of CD8+RHAMM-R3 tetramer+/CD45RA+/CCR7-/CD27-/CD28- effector T cells and an increase of R3-specific CD8+ T cells. In the higher peptide dose cohort three patients showed positive clinical effects. However, higher doses of peptide do not improve the frequency and intensity of immune responses in this clinical trial and might induce immune tolerance. In this work, we investigated the co-existence of serological immune responses against RHAMM detected by a RHAMM-specific ELISA of patients with AML, MDS and multiple myeloma treated in these two peptide vaccination trials. We correlated these results to specific T cell responses of CD8-positive T cells measured by ELISpot assays for interferon gamma and Granzyme B, tetramer staining and chromium release assays. Moreover, these results were compared to the frequency of regulatory T cells. 4/19 patients have a positive serological immune response in ELISA assay, all of these patients developed also strong specific CD8-positive T cell responses during peptide vaccination detected by ELISpot assays and tetramer staining. As expected, peptide vaccination did not result in the induction of humoral immune responses. In further ELISA assays we measured IL-2 and IL-10 levels in the sera of the patients before and three weeks after four vaccinations. While IL-10 levels remained at a rather low level over the time of vaccination, we detected an increase of IL-2 up to the five-fold of the initial levels in four of ten patients. Moreover, we performed a proteome array to detect cytokine and chemokine regulation in sera of patients vaccinated in these two trials during and after RHAMM-R3 peptide vaccination. 36 cytokines, chemokines and acute phase proteins were measured and both cohorts vaccinated with different peptide doses were compared. Taken together, RHAMM-R3 peptide vaccination induced both immunological and clinical responses. Co-existence of immune responses of CD4-positive T cells against the target RHAMM seems to be important for an induction of strong immune responses of CD8-positive T cells. Disclosures: No relevant conflicts of interest to declare.

Mutated Nucleophosmin 1 (NPM1) Is an Immunogenic Target and Patients with NPM1mut Acute Myeloid Leukemia (AML) Showed High Expression of Different Leukemia-Associated Antigens (LAAs)

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3592-3592
Author(s):  
Susanne Hofmann ◽  
Vanessa Schneider ◽  
Lars Bullinger ◽  
Yoko Ono ◽  
Anita Schmitt ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Microarray Analysis ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
High Expression ◽  
Chromium Release ◽  
Cell Responses ◽  
Favorable Prognosis

Abstract Abstract 3592 Nucleophosmin gene 1 mutations (NPM1mut) are one of the most frequent molecular alterations in AML and distinct immune responses might contribute to the favorable prognosis of AML patients with NPM1mut. Recently, we showed specific T cell responses of CD4+ and CD8+ T cells against epitopes derived from mutated regions of NPM1 (Greiner et al., Blood. 2012 May 16, Epub). In the present study, we investigated clinical parameters and the clinical outcome of NPM1mut AML patients in accordance to their immune responses against different NPM1 epitopes. Moreover, we examined the quantitative expression of different leukemia-associated antigens (LAAs) in NPM1mutAML patients. In ELISpot analysis of 33 healthy volunteers and 27 AML patients, we detected T cell responses of CD4+ and CD8+ T cells against epitopes derived from the mutated region of NPM1. We performed further tetramer assays against the most interesting epitopes and chromium release assays to show the cytotoxicity of peptide-specific T cells. Microarray analysis was performed to analyze the expression of different LAAs in NPM1mut and NPM1wtAML patients. Two epitopes (peptide #1 and #3) derived from NPM1mut induced CD8+ T cell responses. 33% of the NPM1mut AML patients showed immune responses against peptide #1 and 44% against peptide #3. NPM1mut AML patients showed a significantly higher frequency of T cell responses against peptide #3 in contrast to HVs (p=0.046), whereas for peptide #1 the frequency of T cell responses of AML NPM1mut patients and HVs was not significantly different. Specific lysis of pulsed T2 cells but also NPM1mut leukemic blasts was detected in chromium release assays. Therefore, overlapping peptides (OL) were analyzed in ELISpot assays and the peptide called OL8 showed favorable results to activate both CD8+ and CD4+ T cells. We performed survival analysis for these 33 NPM1mut patients analyzed by ELISpot comparing cases with or without specific T cell responses. Our data suggest a trend to a better overall survival (OS) for patients with specific T cell responses against peptide #1 or #3. However, the patient numbers are small and the data have to be interpreted carefully. Analyses with material from larger controlled clinical trials with a high number of patients with NPM1mut AML have to be performed. Our microarray analysis of 30 AML patients showed a high expression of different LAAs like RHAMM, WT-1 and BCL-2 in all subtypes of cells of NPM1mutAML patients, also in leukemic progenitor cells. This demonstrates that NPM1 is an AML subtype suitable for poly-targeted immunotherapeutic trials. Taken together, NPM1mut might constitute an interesting target structure for individualized immunotherapeutic approaches in NPM1mut AML patients. We hypothesize that immune responses to NPM1 mutation may contribute to the favorable prognosis. Disclosures: No relevant conflicts of interest to declare.

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