Genome Wide DNA Methylation Landscape Reveals Glioblastoma Mediated Epigenetic Modification in Tumor Infiltrating CD4+ T-Cells

Abstract INTRODUCTION CD4+ helper T (Th) cells initiate and maintain adaptive immune responses and play a critical role in orchestrating effective antitumor immune response. Although recent immunotherapeutic strategies have shown promising results against glioblastoma, the full potential of this modality has yet to be achieved. One of the major limitations of immunotherapy is the poor efficacy of antiglioblastoma T-cell response in the tumor microenvironment. We hypothesized that glioblastoma modulates antitumor T-cell response by epigenetic modification of tumor infiltrating Th cells (TIThC). METHODS To investigate the influence of glioblastoma on TIThCs, we isolated CD4+ T-cells from the tumor and peripheral blood (PB) of 5 steroid naïve patients with newly diagnosed glioblastoma and performed whole-genome bisulfite sequencing (WGBS) as well as RNAseq and identified differentially methylated and expressed genes between the two cell populations. RESULTS Our results show that glioblastoma mediated epigenetic modifications define the molecular characteristics of glioblastoma infiltrating CD4+ T-cells. Tegmentation based WGBS revealed more than 25 000 regions that are methylated differentially in pairwise comparison of TIThC and PB CD4+ T-cells. Methylation status correlated with the gene expression profile with more than 20 000 differentially expressed genes in TIThCs compared to PB. Of the CD4 lineage specific genes, TBX21, GATA3, RORC, and FOXP3, TBX21, GATA3, and FOXP3 showed differential methylation and expression level in TIThC; whereas, RORC only showed difference in methylation status but not in gene expression level. There was a significant difference in overall and CD4 lineage specific methylation and gene expression profile between patients. Pathway analysis of differentially methylated regions and differentially expressed genes indicated several pathways of tumor induced deregulation, including those involved in T-cell activation, lymphocyte differentiation, regulation of immune effector process, and cytokine production. CONCLUSION Glioblastoma multiforme (GBM) regulates antitumor immune response by significant epigenetic reprogramming of TIThC; thus, influencing their lineage specific differentiation and function.

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Staphylococcal enterotoxins modulate the effector CD4+ T cell response by reshaping the gene expression profile in adults with atopic dermatitis

Scientific Reports ◽

10.1038/s41598-019-49421-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Raquel Leao Orfali ◽

Fabio Seiti Yamada Yoshikawa ◽

Luanda Mara da Silva Oliveira ◽

Natalli Zanete Pereira ◽

Josenilson Feitosa de Lima ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

Atopic Dermatitis ◽

T Cell ◽

Gene Expression Profile ◽

Expression Profile ◽

Cell Response ◽

T Cell Response ◽

T Cell Anergy ◽

Cell Anergy

Abstract Staphylococcus aureus colonizes the skin of atopic dermatitis (AD) individuals, but the impact of its enterotoxins on the chronic activation of CD4+ T cells demands further analysis. We aimed to analyze the CD4+ T cell anergy profile and their phenotypic and functional features through differential expression of cellular activation markers, cytokine production and response to staphylococcal enterotoxin A (SEA). A panel of 84 genes relevant to T cell anergy was assessed by PCR array in FACS-sorted CD4+ T cells, and the most prominent genes were validated by RT-qPCR. We evaluated frequencies of circulating CD4+ T cells secreting single or multiple (polyfunctional) cytokines (IL-17A, IL-22, TNF, IFN-γ, and MIP-1β) and expression of activation marker CD38 in response to SEA stimulation by flow cytometry. Our main findings indicated upregulation of anergy-related genes (EGR2 and IL13) promoted by SEA in AD patients, associated to a compromised polyfunctional response particularly in CD4+CD38+ T cells in response to antigen stimulation. The pathogenic role of staphylococcal enterotoxins in adult AD can be explained by their ability to downmodulate the activated effector T cell response, altering gene expression profile such as EGR2 induction, and may contribute to negative regulation of polyfunctional CD4+ T cells in these patients.

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MOG extracellular domain (p1–125) triggers elevated frequency of CXCR3+ CD4+ Th1 cells in the CNS of mice and induces greater incidence of severe EAE

Multiple Sclerosis Journal ◽

10.1177/1352458514524086 ◽

2014 ◽

Vol 20 (10) ◽

pp. 1312-1321 ◽

Cited By ~ 5

Author(s):

Jyothi T Mony ◽

Reza Khorooshi ◽

Trevor Owens

Keyword(s):

T Cells ◽

T Cell ◽

Cell Response ◽

Cd4 T Cells ◽

Cd8 T Cell ◽

Interferon Γ ◽

T Cell Response ◽

Receptor Expression ◽

Myelin Proteins ◽

Mhc Ii

Background: Myelin-specific T cells are implicated in multiple sclerosis (MS) and drive experimental autoimmune encephalomyelitis (EAE). EAE is commonly induced with short peptides, whereas in MS, whole myelin proteins are available for immune response. We asked whether immunization with the immunoglobulin-like domain of myelin oligodendrocyte glycoprotein (MOGIgd, residues 1–125) might induce distinct CD4+ T-cell response and/or a stronger CD8+ T-cell response, compared to the 21 amino acid immunodominant MHC II-associating peptide (p35–55). Objectives: Compare both EAE and T-cell responses in C57BL/6 mice immunized with MOGIgd and MOG p35–55. Methods: Cytokine production, and chemokine receptor expression by CD4+ and CD8+ T cells in the mouse central nervous system (CNS), were analyzed by flow cytometry. Results: MOGIgd triggered progression to more severe EAE than MOG p35–55, despite similar time of onset and overall incidence. EAE in MOGIgd-immunized mice was characterized by an increased percentage of CXCR3+ interferon-γ-producing CD4+ T cells in CNS. The CD8+ T-cell response to both immunogens was similar. Conclusions: Increased incidence of severe disease following MOGIgd immunization, accompanied by an increased percentage of CD4+ T cells in the CNS expressing CXCR3 and producing interferon-γ, identifies a pathogenic role for interferon-γ that is not seen when disease is induced with a single Major Histocompatibility Complex (MHC) II-associating epitope.

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CD4+ T cells specific for glycoprotein B from cytomegalovirus exhibit extreme conservation of T-cell receptor usage between different individuals

Blood ◽

10.1182/blood-2007-04-079863 ◽

2008 ◽

Vol 111 (4) ◽

pp. 2053-2061 ◽

Cited By ~ 25

Author(s):

Laura Crompton ◽

Naeem Khan ◽

Rajiv Khanna ◽

Laxman Nayak ◽

Paul A. H. Moss

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Receptor ◽

Cell Response ◽

Cd4 T Cells ◽

Clonal Selection ◽

Cell Receptor ◽

T Cell Response ◽

Cd4 T Cell ◽

Extreme Conservation

Antigen-specific CD8+ cytotoxic T cells often demonstrate extreme conservation of T-cell receptor (TCR) usage between different individuals, but similar characteristics have not been documented for CD4+ T cells. CD4+ T cells predominantly have a helper immune role, but a cytotoxic CD4+ T-cell subset has been characterized, and we have studied the cytotoxic CD4+ T-cell response to a peptide from human cytomegalovirus glycoprotein B presented through HLA-DRB*0701. We show that this peptide elicits a cytotoxic CD4+ T-cell response that averages 3.6% of the total CD4+ T-cell repertoire of cytomegalovirus-seropositive donors. Moreover, CD4+ cytotoxic T-cell clones isolated from different individuals exhibit extensive conservation of TCR usage, which indicates strong T-cell clonal selection for peptide recognition. Remarkably, this TCR sequence was recently reported in more than 50% of cases of CD4+ T-cell large granular lymphocytosis. Immunodominance of cytotoxic CD4+ T cells thus parallels that of CD8+ subsets and suggests that cytotoxic effector function is critical to the development of T-cell clonal selection, possibly from immune competition secondary to lysis of antigen-presenting cells. In addition, these TCR sequences are highly homologous to those observed in HLA-DR7+ patients with CD4+ T-cell large granular lymphocytosis and implicate cytomegalovirus as a likely antigenic stimulus for this disorder.

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Neoantigen-specific CD4+ T-cell response is critical for the therapeutic efficacy of cryo-thermal therapy

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2019-000421 ◽

2020 ◽

Vol 8 (2) ◽

pp. e000421

Author(s):

Peng Peng ◽

Hongming Hu ◽

Ping Liu ◽

Lisa X Xu

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

Tumor Antigen ◽

Cell Response ◽

Antitumor Immunity ◽

T Cell Response ◽

Thermal Therapy ◽

Term Survival

BackgroundTraditional tumor thermal ablations, such as radiofrequency ablation (RFA) and cryoablation, can result in good local control of tumor, but traditional tumor thermal ablations are limited by poor long-term survival due to the failure of control of distal metastasis. Our previous studies developed a novel cryo-thermal therapy to treat the B16F10 melanoma mouse model. Long-term survival and T-cell-mediated durable antitumor immunity were achieved after cryo-thermal therapy, but whether tumor antigen-specific T-cells were augmented by cryo-thermal therapy was not determined.MethodsThe long-term antitumor therapeutic efficacy of cryo-thermal therapy was performed in B16F10 murine melanoma models. Splenocytes derived from mice treated with RFA or cryo-thermal therapy were coincubated with tumor antigen peptides to detect the frequency of antigen specific CD4+ and CD8+ T-cells by flow cytometry. Splenocytes were then stimulated and expanded by αCD3 or peptides and adoptive T-cell therapy experiments were performed to identify the antitumor efficacy of T-cells induced by RFA and cryo-thermal therapy. Naïve mice and tumor-bearing mice were used as control groups.ResultsLocal cryo-thermal therapy generated a stronger systematic antitumor immune response than RFA and a long-lasting antitumor immunity that protected against tumor rechallenge. In vitro studies showed that the antigen-specific CD8+ T-cell response was induced by both cryo-thermal therapy and RFA, but the strong neoantigen-specific CD4+ T-cell response was only induced by cryo-thermal therapy. Cryo-thermal therapy-induced strong antitumor immune response was mainly mediated by CD4+ T-cells, particularly neoantigen-specific CD4+ T-cells.ConclusionCryo-thermal therapy induced a stronger and broader antigen-specific memory T-cells. Specifically, cryo-thermal therapy, but not RFA, led to a strong neoantigen-specific CD4+ T-cell response that mediated the resistance to tumor challenge.

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The Polyomavirus BK Large T-Antigen-Derived Peptide Elicits an HLA-DR Promiscuous and Polyfunctional CD4+T-Cell Response

Clinical and Vaccine Immunology ◽

10.1128/cvi.00487-10 ◽

2011 ◽

Vol 18 (5) ◽

pp. 815-824 ◽

Cited By ~ 17

Author(s):

Bala Ramaswami ◽

Iulia Popescu ◽

Camila Macedo ◽

Chunqing Luo ◽

Ron Shapiro ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

Cell Response ◽

T Antigen ◽

T Cell Response ◽

Peptide Sequence ◽

Large T Antigen ◽

Hla Dr ◽

Ifn Γ

ABSTRACTBK virus (BKV) nephropathy and hemorrhagic cystitis are increasingly recognized causes of disease in renal and hematopoietic stem cell transplant recipients, respectively. Functional characterization of the immune response to BKV is important for clinical diagnosis, prognosis, and vaccine design. A peptide mix (PepMix) and overlapping (OPP) or random (RPP) peptide pools derived from BKV large T antigen (LTA) were used to restimulate 14-day-expanded peripheral blood mononuclear cells (PBMC) from 27 healthy control subjects in gamma interferon (IFN-γ)-specific enzyme-linked immunospot (ELISPOT) assays. A T-cell response to LTA PepMix was detected in 15/27 subjects. A response was frequently observed with peptides derived from the helicase domain (9/15 subjects), while the DNA binding and host range domains were immunologically inert (0/15 subjects). For all nine subjects who responded to LTA peptide pools, the immune response could be explained largely by a 15-mer peptide designated P313. P313-specific CD4+T-cell clones demonstrated (i) stringent LTA peptide specificity; (ii) promiscuous recognition in the context of HLA-DR alleles; (iii) cross recognition of homologous peptides from the polyomavirus simian virus 40 (SV40); (iv) an effector memory phenotype, CD107a expression, and intracellular production of IFN-γ and tumor necrosis factor alpha (TNF-α); (v) cytotoxic activity in a chromium release assay; and (vi) the ability to directly present cognate antigen to autologous T cells. In conclusion, T-cell-mediated immunity to BKV in healthy subjects is associated with a polyfunctional population of CD4+T cells with dual T-helper and T-cytotoxic properties. HLA class II promiscuity in antigen presentation makes the targeted LTA peptide sequence a suitable candidate for inclusion in immunotherapy protocols.

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Race between Retroviral Spread and CD4+ T-Cell Response Determines the Outcome of Acute Friend Virus Infection

Journal of Virology ◽

10.1128/jvi.01225-09 ◽

2009 ◽

Vol 83 (21) ◽

pp. 11211-11222 ◽

Cited By ~ 29

Author(s):

Rebecca Pike ◽

Andrew Filby ◽

Mickaël J.-Y. Ploquin ◽

Urszula Eksmond ◽

Rute Marques ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

Cell Response ◽

Acute Infection ◽

T Cell Response ◽

Friend Virus ◽

Antiviral Immune Response ◽

Ultimate Failure ◽

Necessary And Sufficient

ABSTRACT Retroviruses can establish persistent infection despite induction of a multipartite antiviral immune response. Whether collective failure of all parts of the immune response or selective deficiency in one crucial part underlies the inability of the host to clear retroviral infections is currently uncertain. We examine here the contribution of virus-specific CD4+ T cells in resistance against Friend virus (FV) infection in the murine host. We show that the magnitude and duration of the FV-specific CD4+ T-cell response is directly proportional to resistance against acute FV infection and subsequent disease. Notably, significant protection against FV-induced disease is afforded by FV-specific CD4+ T cells in the absence of a virus-specific CD8+ T-cell or B-cell response. Enhanced spread of FV infection in hosts with increased genetic susceptibility or coinfection with Lactate dehydrogenase-elevating virus (LDV) causes a proportional increase in the number of FV-specific CD4+ T cells required to control FV-induced disease. Furthermore, ultimate failure of FV/LDV coinfected hosts to control FV-induced disease is accompanied by accelerated contraction of the FV-specific CD4+ T-cell response. Conversely, an increased frequency or continuous supply of FV-specific CD4+ T cells is both necessary and sufficient to effectively contain acute infection and prevent disease, even in the presence of coinfection. Thus, these results suggest that FV-specific CD4+ T cells provide significant direct protection against acute FV infection, the extent of which critically depends on the ratio of FV-infected cells to FV-specific CD4+ T cells.

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Loss of EBV-Specific CD4+T Cells during Progression to EBV-Related AIDS Non-Hodgkin Lymphoma: Restoration by Highly Active Antiretroviral Therapy (HAART).

Blood ◽

10.1182/blood.v104.11.3110.3110 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3110-3110

Author(s):

Erwan R. Piriou ◽

Christine Jansen ◽

Karel van Dort ◽

Iris De Cuyper ◽

Nening M. Nanlohy ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Response ◽

Cd4 T Cells ◽

Antigen Processing ◽

Ex Vivo ◽

T Cell Response ◽

Cd4 T Cell ◽

Cell Numbers

Abstract Objective: EBV-specific CD8+ T cells have been extensively studied in various settings, and appear to play a major role in the control of EBV-related malignancies. In contrast, it is still unclear whether EBV-specific CD4+ T cells play a role in vivo. To study this question, an assay was developed to measure the CD4+ T-cell response towards two EBV antigens, in both healthy (n=14) and HIV-infected subjects (n=23). In addition, both HAART-treated (n=12) and untreated HIV+ individuals (n=14) - including progressors to EBV-related lymphoma - were studied longitudinally. Methods: EBV-specific CD4+ T cells were stimulated with peptide pools from latent protein EBNA1 and lytic protein BZLF1, and detected by measurement of IFNg-production. Results: After direct ex vivo stimulation, EBNA1 or BZLF1-specific IFNg- (and/or IL2) producing CD4+ T cell numbers were low, and measurable in less than half of the subjects studied (either HIV- and HIV+). Therefore, PBMC were cultured for 12 days in the presence of peptides and IL2 (from day 3), and then restimulated with peptides, allowing specific and reproducible expansion of EBV-specific CD4+ T cells, independent of HLA type and ex vivo antigen processing. Interestingly, numbers of EBV-specific CD4+ T cells inversely correlated with EBV viral load, implying an important role for EBV-specific CD4+ T cells in the control of EBV in vivo. Untreated HIV-infected individuals had a lower CD4+ T cell response to EBNA1 and BZLF1 as compared to healthy EBV carriers and HAART-treated HIV+ subjects. In longitudinal samples, EBNA1-specific, but not BZLF1-specific T-cell numbers increased after HAART, while EBV load was not affected by treatment. In all the progressors to EBV-related lymphoma, EBV-specific CD4+ T cells were lost at least 24 months before lymphoma diagnosis. Conclusions: Both cross-sectional and longitudinal data suggest an important role for EBV-specific CD4+ T cells in the control of EBV-related malignancies. Furthermore, it seems that HAART treatment leads to recovery of EBNA1-specific, but not BZLF1-specific CD4+ T-cell responses, implying changes in the latency pattern of EBV, despite an unaltered cell-associated EBV DNA load. Thus, early HAART treatment might prevent loss of specific CD4+ T-cell help and progression to NHL.

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Functional Analysis and Gene Expression Profile of Umbilical Cord Blood Regulatory T Cells.

Blood ◽

10.1182/blood.v114.22.4085.4085 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4085-4085

Author(s):

Giovanni Fernando Torelli ◽

Roberta Maggio ◽

Nadia Peragine ◽

Sabina Chiaretti ◽

Maria Stefania De Propris ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

Stem Cell ◽

T Cell ◽

Gene Expression Profile ◽

Expression Profile ◽

Production Capacity ◽

T Cell Response ◽

Foxp3 Gene ◽

Before And After

Abstract Abstract 4085 Poster Board III-1020 Introduction Umbilical cord blood (CB) stem cells are now broadly used in the unrelated stem cell transplant setting and comparative studies with different stem cell sources have shown that CB transplant is characterized by a lower risk of graft-versus-host disease (GVHD). The immaturity of CB T cells has been generally regarded as the main contributing factor accounting for this phenomenon; the possible role played by CB regulatory T cells (Tregs) for the suppression of the allogeneic T-cell response is now under investigation, but very scare data are so far available. Aim of this study was to analyze and compare the functional properties and the gene expression profile of Tregs expanded from CB units with those expanded from the peripheral blood (PB) of adult normal donors. Methods Tregs were purified from mononuclear cells obtained from 23 CB units and from the PB of 13 adult normal donors using the CD4+CD25+ regulatory T-cell isolation kit (Miltenyi Biotec) and expanded for 6 days in 96-well U-Bottom plates coated with the anti-CD3 (5 ug/ml) and anti-CD28 (5 ug/ml) MoAbs in the presence of IL-2 (100 U/ml). Immunophenotypic analyses were performed before and after expansion. To assess their suppressive functions, expanded Tregs were seeded with autologous effector T cells stimulated with allogeneic dendritic cells (DC) pulsed with apoptotic leukemic blasts, then incubated with [3H]-thymidine and counted in a beta-counter. Suppressor activity was measured as [3H]-thymidine incorporation in the presence or absence of Tregs. The IL-10 production capacity of expanded Tregs was tested using an ELISA assay. The two-sided student t test was used to evaluate the significance of differences between groups. Gene expression profile experiments were performed using the HGU133 Plus 2.0 arrays (Affymetrix); statistical analyses were carried out using the dChip software; a t test was used to evaluate the presence of specifically expressed classes of genes. Functional annotation analysis was performed using the DAVID software. Results CB and PB Tregs presented similar immunophenotypic appearances before and after expansion. Im particular, after expansion they presented a comparable expression of surface CD4, CD25, CD62L, CCR5 and CD45RO, and of cytoplasmic CTLA-4 and Foxp3, while they both were negative for the CD45RA antigen, thus indicating the loss of their naïve features. On the contrary, Tregs obtained from CB (n=23) presented a much higher expansion capacity compared to those obtained from PB (n=13): mean fold increase (range), CB 10.3 (1.6-24), PB 3.9 (1.5-10), p 0.003. CB expanded Tregs (n=6) exerted a potent suppressive function on the proliferative reaction of T cells stimulated by allogeneic DC, that resulted inferior even though not significantly compared to that exerted by PB expanded Tregs (n=5): mean fold reduction (range), CB 7.8 (2.5-15.1), PB 14.3 (1.5-23.7), p 0.14. Tregs expanded from CB (n=4) and PB (n=1) presented a high and comparable in vitro IL-10 production capacity: mean pg/ml (range), CB 326.5 (226-426), PB 382. Gene expression profile analysis showed a higher number of upregulated genes in Tregs expanded from CB (n=2) compared to Tregs expanded from PB (n=3); among them, a significant enrichment of genes involved in cell proliferation, cell cycle checkpoints, signal transduction, cell differentiation, apoptosis, TGF-β receptor pathway and the GrNH pathway was observed. This suggests that CB Tregs retain a more undifferentiated program and are characterized by the high expression of genes which might provide an advantage in cell expansion. Finally, when looking at the Foxp3 gene expression levels, no difference was observed between the two populations. Conclusions These results demonstrate that Tregs contained in CB retain an expansion potential superior to that of Tregs isolated from the PB of normal donors, as confirmed by functional analyses and gene profile. Tregs expanded from CB and PB seem to exert a potent and comparable suppressive function of the proliferative effect in mixed lymphocyte reaction assays. The maintaining of the modulatory properties after expansion is confirmed by the expression of the Foxp3 gene and protein, and by the production of IL-10. These data offer further insights into the understanding of the biology of CB transplantation indicating a possible role played by CB Tregs in the suppression of the allogeneic T-cell response. Disclosures: No relevant conflicts of interest to declare.

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Enhancing Cytotoxicity of Autologous T Cells in AML By Blockade of CTLA-4 and PD-1

Blood ◽

10.1182/blood.v128.22.4057.4057 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4057-4057 ◽

Cited By ~ 1

Author(s):

Kirsten Marie Boughan ◽

Xiaohua Chen ◽

Paul Szabolcs

Keyword(s):

Gene Expression ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Response ◽

Conflicts Of Interest ◽

Expression Profiles ◽

T Cell Response ◽

Inhibitory Receptors

Abstract Background: AML remains a disease diagnosed in the aging population with chemotherapy followed by bone marrow transplant in some cases being the standard of care. Although response rates remain around 50-60%, treatment related mortality and disease relapse remain high. Adoptive immunotherapy, especially those targeting T cell co-inhibitory receptors, has proven successful in solid malignancies however, AML remains less explored. Our laboratory has previously demonstrated the feasibility to generate autologous AML reactive T cells in vitro (Mehta/Szabolcs; Immunotherapy 2016). It was noted that "resistant" AML blasts over expressed a number of genes associated with immunosuppressive characteristics. Over expression of these genes may induce T cell functional exhaustion. Therefore, we hypothesized that blocking PD-1 and/or CTLA-4 during co-culture with IFNg activated AML blasts, may enhance T cell activation and cytotoxicity. To test this hypothesis, we tested CTL responses against AML blasts and IFNg ELISpot formation after blocking with PD-1, CTLA-4 or both receptors, and compared the response in untreated T cells. Gene expression profiles of co-stimulatory/co-inhibitory receptors were also monitored to test for correlation. Methods: We evaluated 12 patients with newly diagnosed AML under an IRB approved protocol with written informed consent of patients. Mononuclear cell preparation was generated from fresh marrow samples or drawn from a biorepository of previously cryopreserved leukophereses. T cells were then purified using immunomagnetic CD3/CD28 beads (Life technologies) and cultivated in media with IL-2 and IL-7 for 2 weeks. AML blasts were cultured over a supporting layer of mesenchymal stromal cells (MSCs) derived from healthy BM donors for 1 week and then cryopreserved. T cells were then co-cultured with restored and irradiated autologous AML cells at an effector: target (E: T) ratio of 5:1 to 40:1. AML and T cells were co-cultured in the presence of Ipilimumab (anti-CTLA-4), or Nivolumab (anti-PD-1), or a combination of both drugs. T cells and AML were re stimulated in X-vivo 15 with IL-12, IL-15 and IL-2 weekly x 3weeks. T cell response to AML was quantitated by IFNg ELISpot assay and Europium TDA (EuTDA) CTL assays independently. Co-stimulatory/co-inhibitory expression on T cells was examined with RT-q PCR assay. Paired-sample student t test was used for statistical analysis with p<0.05. Results and Discussion: Out of 12 samples, 10 (83%) yielded viable AML cells available for cytotoxicity assay. One third (33%) of co-cultures exhibited a positive T cell response in CTL assays ("killers"). There was no difference in CTL activity by blockade of either PD-1 or CTL-4 (Fig 1). IFN-ɣ spot formation in ELISpot was observed in 4/10 samples (40%) with statistical significance noted in cells blocked with PD-1 as compared to all other blockade types (Fig 2). The results indicated that in vitro priming with autologous AML blasts or together with blocking PD-1 can enhance T cell response in 33-40%. By gene expression analysis, the ratio of co-stimulatory to co-inhibitory genes was calculated. In PD-1 blocked cells, the ratio of activation/inhibition was not impacted in T cells from "killers" (0.9; p=0.1), however, T cells from "non-killer cells" had a diminished ratio due to higher expression of co-inhibitory molecules (0.4; p=0.04) (Fig 3). This trend was also present in CTLA-4 blocked cells (0.85; p=0.4 in killers vs 0.54; p=0.03 in non-killers) (data not shown). Interestingly, dual blockage failed to influence gene expression ratio, data not shown. Conclusion: The above studies demonstrate that cytotoxicity can be achieved in T cells when primed against autologous AML. PD-1 blockade can enhance IFNg production and cytotoxic responses, but CTLA-4 and dual blockade failed to enhance T cell function. The upregulation of an inhibitory pattern of genes in T cells that did not express cytotoxicity (non-killers) could allude to an "inhibitory phenotype" that may be resistant to immunotherapy drug blockade and requires further study. Disclosures No relevant conflicts of interest to declare.

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

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.21032 ◽

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.

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