scholarly journals Specific Immune Responses for Leukemia-Associated Antigens Against Myeloid Leukemic Cells Are Increased By Immune Checkpoint Inhibition

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4054-4054 ◽  
Author(s):  
Jochen Greiner ◽  
Marlies Götz ◽  
Vanessa Schneider ◽  
Hubert Schrezenmeier ◽  
Markus Wiesneth ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Immune Checkpoint ◽  
Cytotoxic T Cells ◽  
T Cell Responses ◽  
Leukemic Cells ◽  
Cell Responses ◽  
Cell Assays ◽  
T Cell Assays

Abstract Immunotherapy in cancer treatment has gained importance in the last few years. The efficacy of immunotherapeutic approaches such as immune-checkpoint inhibitors, chimeric antigen receptor T cells (CARs) or bi-specific T cell activating antibodies becomes more and more obvious. However, mechanisms of these immune responses and responsible antigen structures have to be further elucidated. Leukemia-associated antigens (LAA) represent immunogenic antigens that are candidates for specific immunotherapy since they are target structures relevant for elimination of malignant cells by cytotoxic T cells (CTL). In this work, we investigated the influence of PD-1 antibody Nivolumab and CTLA-4 antibody Ipilimumab on the antigen-specific immune responses by specific T cells against leukemic myeloid blasts in functional T cell assays using ELISpot Assays, tetramer-analysis and colony-forming immunoassays. We investigated T cell responses stimulated against known LAAs like RHAMM, PRAME, WT-1, SSXIP2, Proteinase 3, Survivin, Aurorakinase A and NPM1 against several AML cell lines and samples of AML patients. Expression of different LAAs were measured and correlated to functional T cell assays. Colony forming unit immunoassays displayed a significant inhibition of CFU (colony forming units) in AML patient samples when adding T cells stimulated against various LAA. In all patient samples, effectors activated against at least one LAA were successful to decrease the colony number significantly. The LAAs PRAME, RHAMM and WT1 showed highest frequency and intensity of immunogenic reactions: PRAME stimulated CTL induced an immune response in 83% of tested samples in CFU, stimulated with WT1 in 75% and with RHAMM in 58% of colonies from AML samples. Specific immune responses of cytotoxic T cells were additionally detected by ELISpot assays and correlated to results detected in CFU. Immune effects increased adding nivolumab to the CTL for several days before starting CFU immunoassays whereas no effect was measured when CTL were incubated with Ipilimumab. The combination of Nivolumab and Ipilimumab showed no additional effect of immune responses compared to Nivolumab alone. Taken together, the immune checkpoint inhibitor Nivolumab increases specific T cell responses of LAA-stimulated cytotoxic T cells and the cytotoxic effect of T cells against blasts of AML patients. No additional effect was detected with Ipilimumab. These data suggest that PD-1 antibodies could be an immunotherapeutic approach in AML and combination with LAA-directed vaccination strategies might open interesting application possibilities. Disclosures Greiner: BMS: Research Funding.

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.

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 Neonates Mount Robust and Protective Adult-Like CD8+-T-Cell Responses to DNA Vaccines

2002 ◽  
Vol 76 (23) ◽  
pp. 11911-11919 ◽  
Author(s):  
Jie Zhang ◽  
Nicole Silvestri ◽  
J. Lindsay Whitton ◽  
Daniel E. Hassett
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Viral Infections ◽  
Dna Vaccines ◽  
Neonatal Period ◽  
Cytotoxic T Cells ◽  
Lymphocytic Choriomeningitis ◽  
Cell Responses ◽  
Rapid Induction

ABSTRACT Neonates are thought to mount less vigorous adaptive immune responses than adults to antigens and infectious agents. This concept has led to a delay in the administration of many currently available vaccines until late infancy or early childhood. It has recently been shown that vaccines composed of plasmid DNA can induce both humoral and cell-mediated antimicrobial immunity when administered within hours of birth. In most of these studies, immune responses were measured weeks or months after the initial vaccination, and it is therefore questionable whether the observed responses were actually the result of priming of splenocytes within the neonatal period. Here we show that DNA vaccination at birth results in the rapid induction of antigen-specific CD8+ T cells within neonatal life. Analyses of T-cell effector functions critical for the resolution of many viral infections revealed that neonatal and adult CD8+ T cells produce similar arrays of cytokines. Furthermore, the avidities of neonatal and adult CD8+ T cells for peptide and the rapidity with which they upregulate cytokine production after recall encounters with antigen are similar. Protective immunity against the arenavirus lymphocytic choriomeningitis virus, which is mediated by CD8+ cytotoxic T cells, is also rapidly acquired within the neonatal period. Collectively these data imply that, at least in the case of CD8+ T cells, neonates are not as immunodeficient as previously supposed and that DNA vaccines may be an effective and safe means of providing critical cell-mediated antiviral immunity extremely early in life.

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.

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.

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.

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