P06.14 Characterization of tumor-infiltrating T cells by highly multiplexed immunofluorescence imaging

BackgroundThe adoptive cell transfer (ACT) of tumor-infiltrating T lymphocytes (TILs) has shown remarkable results in patients with different cancer types. The antitumor effect of this therapy is mainly attributed to a small fraction of tumor-reactive T lymphocytes (TRLs) that recognize mutated peptides as well as overexpressed self-antigens. Therefore, the enrichment and expansion of TRLs constitutes a promising immunotherapy approach. However, the specific targeting of individual mutated antigens represents a daunting challenge for widespread therapeutic application. Alternatively, we hypothesize that TRLs could be identified and enriched by a surface marker (or combination thereof) in an antigen-independent manner as a result of the chronic antigen exposure and other factors present in the tumor microenvironment (TME).Materials and MethodsWe screened T cell activation and exhaustion markers, among others, on different tumor tissues using the MACSima™ Imaging Platform, an instrument for the highly multiplexed immunofluorescence imaging technology MICS (Multiparameter Imaging Cell Screen), enabling investigation of hundreds of markers on a single section. Moreover, flow cytometry and single-cell RNA sequencing analyses of T cells from tumor digests were performed to complement the characterization of TILs.ResultsThe MICS results highlighted the complexity of the TME, mainly composed of tumor cells, fibroblasts and endothelial vessels. In some cases, an extensive immune infiltrate consisted of T cells, plasma cells, some B cells and distinct myeloid cells was observed. Particularly, CD8 T cells from different tumor areas exhibited a tissue-resident memory phenotype with the expression of CD69, CD45RO or CD103. Activated/exhausted CD8 T cells were homogenously found across the imaged tumor areas. However, there was a tendency to find them in close proximity to tumor cells, especially for CD8 subsets expressing CD39 and other relevant markers, which may suggest the identification of tumor-reactive CD8 T cell populations. Flow cytometry data revealed the presence of similar T cell phenotypes in the patient´s TILs from tumor digests.ConclusionsThis imaging technology offers the possibility to study multiple parameters—including the localization—of relevant cells in the TME such as T cells. The phenotypic and functional characterization of different T cell subsets will allow the further investigation of their anti-tumor reactivity. Ultimately, the enrichment and expansion of the identified tumor-reactive T cell population hold great promises to improve the efficiency of T cell therapy against cancer.Disclosure InformationE. Criado-Moronati: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. A. Gosselink: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. J. Kollet: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. A. Dzionek: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG. B. Heemskerk: A. Employment (full or part-time); Significant; Miltenyi Biotec B.V. & Co. KG.

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PD-1+ T Cell Subsets in Follicular Lymphoma Tumor Microenvironment and Their Implications for Prognosis and Therapy

Blood ◽

10.1182/blood.v118.21.2648.2648 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2648-2648

Author(s):

Fuliang Chu ◽

Wencai Ma ◽

Tomohide Yamazaki ◽

Myriam Foglietta ◽

Durga Nattama ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

T Cell ◽

Follicular Lymphoma ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

T Cell Subsets ◽

Prognostic Impact ◽

T Cell Exhaustion ◽

Cell Exhaustion

Abstract Abstract 2648 Background: Programmed death (PD)-1, a coinhibitory receptor expressed by effector T cells (Teffs) is highly expressed on intratumoral T cells (mean 61%, range 34–86% for CD4+ T cells and mean 44%, range 31–69% for CD8+ T cells) in follicular lymphoma (FL), a finding associated with impaired ability to recognize autologous tumor (Nattamai et al, ASH 2007). Hence, PD-1 expression would be expected to confer an unfavorable prognosis in FL. However, correlation of PD-1 with clinical outcome in FL has been inconsistent with two studies showing favorable (Carreras et al, J Clin Oncol 2009; Wahlin et al, Clin Cancer Res 2010) and one study showing unfavorable (Richendollar et al, Hum Pathol 2011) outcome. While differences in method of analysis and type of treatment may explain the disparate results, a more complex model may be necessary to understand the prognostic impact of PD-1 in FL as PD-1 is expressed not only on antitumor Teffs but also on protumor follicular helper T cells (Tfh) and regulatory T cells (Tregs). Methods: To determine the nature of PD-1+ T cells in FL we performed comprehensive genomic and immunologic studies. By flow cytometry, we observed that the intratumoral CD4+ T cells in FL may be categorized into 3 subsets based on PD-1 expression - PD-1 high (PD-1hi), intermediate (PD-1int), and low (PD-1lo). The intratumoral CD8+ T cells consisted of PD-1int and PD-1lo subsets. The 3 CD4+ T cell subsets were FACSorted from FL tumors (n=3) and whole genome gene expression profiling (GEP) was performed. T cell subsets sorted similarly from tonsils served as controls for reactive follicular hyperplasia (FH) (n=3). Differentially expressed genes in GEP studies were confirmed at the mRNA level by real-time PCR (n=5) and at the protein level by flow cytometry when antibodies were available (n=5–10). Results: Our results suggested that CD4+PD-1hi T cells are Tfh cells (CXCR5hiBcl6hi ICOShiCD40LhiSAPhiPRDM1loIL-4hiIL-21hi); the CD4+PD-1int T cells consisted of a mixture of activated Teffs (CD45RO+CD45RA−) including Th1 (Tbet+IFNg+), Th2 (IL-10+), and Th17 cells (RORc+IL-17+), and Tregs (Foxp3+CD25hiCD127lo); and the CD4+PD-1lo T cells consisted of a mixture of activated Teffs (CD45RO+CD45RA− but IFNg−IL-4−IL-10−IL-17−), Tregs, and naïve T cells (CD45RO−CD45RA+CCR7+). Although these subsets were present in both FL and FH, there were important differences. IL-4 expression was significantly higher in Tfh in FL vs. FH and may play a role in the pathogenesis of FL. IL-17 expression was low and expression of coinhibitory molecules BTLA and CD200 was high in CD4+PD-1int T cells in FL vs. FH. BTLA and CD200 were also increased in CD8+PD-1int T cells in FL vs. FH. However, other coinhibitory molecules (LAG-3, Tim-3, CD160, CTLA-4, CD244, KLRG1) were not significantly different between FL and FH. CD4+PD-1int T cells also had higher expression of BATF, a transcription factor associated with T cell exhaustion in FL vs. FH. Together, these results suggest that the CD4+PD-1int T cells in FL may be in a state of T cell exhaustion whereas the CD4+PD-1int T cells in FH may represent recently activated Teffs. Consistent with this, blocking PD-1 with anti-PD-1 blocking antibody significantly enhanced proliferation and the production of Th1 (IFNg, TNFa) but not Th2 (IL-4, IL-5, IL-10, IL-13) cytokines by intratumoral CD4+ and CD8+ T cells in response to stimulation with autologous FL tumor cells (n=3). As expected, Tregs were increased in number in FL vs. FH and were present in the PD-1int and PD-1lo T cell subsets. We found 74% (range 40–97%) of FL Tregs expressed PD-1. Among the CD4+PD-1lo and CD8+PD-1lo T cells, there were more activated Teffs and fewer naïve T cells in FL vs. FH. Conclusions: Our results suggest that the PD-1+ T cells in FL are comprised of a mixture of antitumor Teffs and protumor Tfh and Tregs. The prognostic impact of PD-1+ T cells in FL may dependent on the relative frequency of these subsets as ligation of PD-1 may produce favorable (inhibition of protumor Tfh and Tregs) or unfavorable (inhibition of antitumor Teffs) outcomes by inhibiting or promoting tumor growth, respectively. Conversely, our results imply that agents that block PD-1/PD-ligand pathway may have the opposite effect on these T cell subsets and enumeration of the intratumoral PD-1+ T cell subsets may serve as biomarker to predict response to these agents in FL and possibly other B-cell malignancies. Disclosures: Dong: GSK: Consultancy; Genentech: Honoraria; Tempero: Consultancy; Ono: Consultancy; AnaptysBio: Consultancy. Neelapu:Cure Tech Ltd: Research Funding.

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Characterization of CD4-Positive Lymphocytes in the Antiviral Response of Olive Flounder (Paralichthys oliveceus) to Nervous Necrosis Virus

International Journal of Molecular Sciences ◽

10.3390/ijms21114180 ◽

2020 ◽

Vol 21 (11) ◽

pp. 4180

Author(s):

Jae Wook Jung ◽

Jin Hong Chun ◽

Jung Seok Lee ◽

Si Won Kim ◽

Ae Rin Lee ◽

...

Keyword(s):

Flow Cytometry ◽

Immune Response ◽

T Cells ◽

T Cell ◽

T Lymphocytes ◽

Viral Infection ◽

T Cell Subsets ◽

Olive Flounder ◽

Flow Cytometry Analysis ◽

Color Flow

The presence of CD4 T lymphocytes has been described for several teleost species, while many of the main T cell subsets have not been characterized at a cellular level, because of a lack of suitable tools for their identification, e.g., monoclonal antibodies (mAbs) against cell markers. We previously described the tissue distribution and immune response related to CD3ε and CD4-1 T cells in olive flounder (Paralichthys oliveceus) in response to a viral infection. In the present study, we successfully produce an mAb against CD4-2 T lymphocytes from olive flounder and confirmed its specificity using immuno-blotting, immunofluorescence staining, flow cytometry analysis and reverse transcription polymerase chain reaction (RT-PCR). Using these mAbs, we were able to demonstrate that the CD3ε T cell populations contain both types of CD4+ cells, with the majority of the CD4 T cell subpopulations being CD4-1+/CD4-2+ cells, determined using two-color flow cytometry analysis. We also examined the functional activity of the CD4-1 and CD4-2 cells in vivo in response to a viral infection, with the numbers of both types of CD4 T cells increasing significantly during the virus infection. Collectively, these findings suggest that the CD4 T lymphocytes in olive flounder are equivalent to the helper T cells in mammals in terms of their properties and function, and it is the CD4-2 T lymphocytes rather than the CD4-1 T cells that play an important role in the Th1 immune response against viral infections in olive flounder.

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Identification and Isolation of Tumor-Specific Cytotoxic T Lymphocytes in Acute Myeloid Leukemia Patients through the Identification of T-Cells Capable to Establish Stable Interactions with Leukemic Cells

Blood ◽

10.1182/blood-2018-99-118118 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3336-3336

Author(s):

Estefania Garcia-Guerrero ◽

Luis I. Sanchez-Abarca ◽

Esther Domingo ◽

Teresa Ramos ◽

Jose Antonio Bejarano-García ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

Acute Myeloid Leukemia ◽

T Cell ◽

T Lymphocytes ◽

Tumor Cells ◽

Cd8 T Cells ◽

Myeloid Leukemia ◽

Target Cells ◽

Acute Myeloid

Abstract Introduction Autologous adoptive T cell therapies, based on the use of tumor infiltrating lymphocytes (TILs), have made great progress in recent years for the treatment of solid tumors, especially melanoma. However, further work is needed to isolate tumor-reactive T cells among patients diagnosed with hematologic malignancies. The dynamics of the interaction between T cells and antigen presenting cells (APC) dictate the quality of the immune responses. While stable joints between target cells and T lymphocytes lead to the induction of T cell activation and immune response, brief contacts contribute to the induction of immune-tolerance. Taking advantage of the strong interaction between target cell and activated T-cells, we show the feasibility to identify and isolate tumor-specific cytotoxic T lymphocytes (CTLs) from acute myeloid leukemia (AML) patients. Using this approach, CTLs stably bound through T cell receptor to tumor cells (doublet forming T-cells) can be identified in peripheral blood and bone marrow and subsequently selected and isolated by FACS-based cell sorting. Methods Co-cultures between PBMC from AML patients in complete remission and AML tumor cells (PKH-stained) from the same patient were performed to study the percentage of doublet-forming T cells (CD3+PKH+) (T cell bound to a tumor cell). After 15 hours of co-culture, cells were stained and sorted. Secondary co-cultures with autologous tumor cells (used in primary co-culture) were performed to study the cytotoxic activity and cytokine production of T-cells capable or not to form stable joints with the leukemic cells (doublet population vs non-doublet population). Results Doublet-forming T cells from AML patients were identified in a range of 2% to 6% (mean=3.83%, n=5). Immunophenotyping analysis showed differences between doublet-forming T cells (CD3+PKH+) and those T cells which did not form stable and strong interactions with target cells (CD3+PKH-). Doublet T cells displayed a higher percentage of CD8+ T cells and higher percentage of effector CD4+ and CD8+ T cells compared to non-doublet T cells. Next, we explored, among effector CD4+ and CD8+ cells, those with cytotoxic phenotype. As expected, a high percentage of effector CD8+ doublet T cells showed Granzyme B and perforin expression, thus corresponding with a cytotoxic immune-phenotype (n=3, mean 65.51%). Within effector CD4+ doublet T cells, a mean of 9.053 % showed expression of both Granzyme B and perforin corresponding with CD4+ CTL (n=3). Regarding CD57 and CD16 markers, a mean of 18.62% of effector CD4+ doublet T cells were positive for both markers, compared to 65.84% of effector CD8+ doublet T cells (n=3). Further, we performed secondary co-cultures to analyze the CD69 activation marker after 24h of co-culture. A high percentage of CD69+ cells was observed in co-cultures with doublet-forming T cells against target cells as compared to non-doublet T cells (n=3, p=0.0053). Finally, analysis of supernatants of co-culture of doublet T cells and non-doublet T cells with target cells revealed specific secretion of IFNγ and IL-2 (n=3, p=0.0001; p=0.0005, respectively). The cytolytic activity was evaluated comparing the viability of tumor cells cultured alone or with doublet-forming T cells or non-doublet T cells from the same patient. A significant increase of the specific lysis of AML cells was observed when doublet T cells were co-cultured as compared to non-doublet T cells (p=0.0424, n=5). This encouraged us to examine whether we were able to identify doublet-forming T cells from bone marrow of AML patients at diagnosis. Analyses of bone marrow by flow cytometry reveled a small percentage of CD3+CD34+ population corresponding with bone marrow-doublet-forming T cells (n=3, mean=2.9%). Interestingly, bone marrow-doublet-forming T cells show a higher percentage of CD4+ T cells, whereas bone marrow-non-doublet T cells show a higher percentage of CD8+ T cells. Conclusions Our data demonstrate that when T cells from AML patients are co-cultured with tumor cells, a "doublet T cell" population appears. This population consists of T cells capable to bind tumor cells. These CTLs display higher percentage of effector cells and a marked cytotoxic activity against AML blasts. In conclusion, we have developed a new procedure to identify and select specific cytotoxic T cells in both bone marrow and peripheral blood from patients diagnosed with acute myeloid leukemia. Figure. Figure. Disclosures Sanchez-Abarca: Virgen del Rocio University Hospital: Patents & Royalties. Ramos:Takeda Oncology: Research Funding.

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Bone Marrow GZMK +IL7R + Progenitor-Exhausted CD8 + T Cells Correlate with Sustained Clinical Remission in Patients with Acute Myeloid Leukemia (AML) Undergoing Chemotherapy

Blood ◽

10.1182/blood-2021-149150 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 521-521

Author(s):

Francesco Mazziotta ◽

Luca Biavati ◽

Rupkatha Mukhopadhyay ◽

Hanna A. Knaus ◽

Ivan M. Borrello ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Myeloid Leukemia ◽

Cd8 T Cell ◽

T Cell Subsets ◽

Spectral Flow

Abstract Introduction The role of T cells in chemotherapy response and maintenance of remission in acute myeloid leukemia (AML) patients is not fully understood. In solid tumors and chronic infections, exhaustion is a multistep process ranging from less differentiated progenitor exhausted (Tpex) to intermediate and terminally exhausted T cells (Beltra et al. 2020). High frequencies of Tpex correlate with response to immune-checkpoint blockade in solid tumors (Miller et al. 2019). In AML, where the backbone of treatment is chemotherapy, the role of dysfunctional T-cell subsets has yet to be elucidated. Methods Serial bone marrow (BM) samples from 16 AML patients (10 complete responders (Res) and 6 non-responders (NonRes)) at diagnosis and at response assessment after induction chemotherapy and 12 healthy donors (HD) were analyzed by flow cytometry using a 13-color panel. Moreover, we performed single-cell RNA sequencing (scRNAseq) (10X Genomics) on BM samples from 2 HD and 5 AML patients (3 Res, 2 NonRes) at baseline and after chemotherapy. Subsequently, we used a scRNAseq-guided 26-color spectral flow cytometry panel and explored T-cell phenotypes on BM of 22 AML patients (12 Res and 10 NonRes). Custom-made R scripts were employed for high-dimensional flow cytometry and scRNAseq analysis. Results Initial flow-cytometry analysis showed a significant increase in BM PD1 +CD28 + CD8 + T cell subset (p<0.01) in Res vs NonRes at baseline and post-chemotherapy (data not shown). To further investigate these results, we performed 5' VDJ scRNAseq and used gene signatures mapped in two dimensions via UMAP to annotate the T-cell clusters as naive, Tpex, T effector CX3CR1 + (Teff CX3CR1pos), Terminally exhausted 1 (Term_exh1) and Terminally exhausted 2 (Term_exh2) (Fig 1A). Of note, the two most upregulated genes in Tpex were GZMK and IL-7R. We then performed differential abundance analysis to investigate differences in terms of clusters' frequencies across the three conditions (Res, NonRes, HD). At both timepoints Res had an increased frequency of Tpex and Teff CX3CR1pos compared to NonRes. Conversely, Term_exh2 cells were more abundant in NonRes (Fig. 1B). Next, we measured the magnitude of clonal expansion in antigen-experienced CD8 + T cells in Res and NonRes generating an overlay of the position of clonally expanded cells projected onto the UMAP. The most clonally expanded subsets were Tpex and Teff CX3CR1pos in Res (Fig. 1C) and Term_exh2 in NonRes (Fig. 1D) revealing a strong relationship between abundance and clonal expansion of the CD8 + T-cell subsets. Our scRNAseq results were then confirmed at the protein level with spectral flow-cytometry. The FlowSOM algorithm identified a CD8 + GZMK +CD127 + subset to be increased at baseline in Res vs NonRes (Fig. 1E). Remarkably, this cluster was also characterized by the expression of TIGIT, PD1 and TCF-1. These results were subsequently reproduced by manual gating of the GZMK +CD127 + subset which was significantly enriched (p<0.01) in Res vs NonRes (Fig. 1F). Of note, patients with a higher-than-median frequency of GZMK +CD127 +CD8 + T cells experienced significantly (p<0.02) prolonged overall survival after therapy (Fig. 1G). Conclusion Improving our understanding of the immune microenvironment in AML is critical for the rational integration of novel treatment strategies that seek to increase the response rate and/or maintain remission. We identified GZMK +IL7R + CD8 + cells as a distinct entity in the early differentiated CD8 + memory T cell pool that is clonally expanded and more abundant in Res compared to NonRes. This subset has a stem-like signature and may be associated with longer in vivo CD8 + T cell persistence and long-term AML control. An in-depth functional characterization with in vitro experiments and in vivo mouse models is currently ongoing. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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Phenotype, Function, and Safety of a p53 TCR Bicistronic GMP-Suitable Retroviral Construct.

Blood ◽

10.1182/blood.v108.11.3695.3695 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3695-3695

Author(s):

Florian Rohrbach ◽

Gunda Brandenburg ◽

Edite Antunes Ferreira ◽

Vera Wimmenauer ◽

Daniel Hirsch ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Suppressor ◽

Tumor Cells ◽

Cd8 T Cells ◽

Adoptive Transfer ◽

T Cell Subsets ◽

Class I ◽

High Affinity ◽

Self Tolerance

Abstract Malignant transformation of normal cells is frequently correlated with the involvement of so called tumor-associated antigens (TAA). Such proteins, that are often overexpressed in tumor cells, can be recognized by cytotoxic CD8+ T cells (CTL) if presented as peptides on MHC (Major-Histocompatibility-Complex)-class I molecules. Due to self-tolerance mechanisms, the peripheral T cell repertoire is devoid of efficient TAA-specific, tumor-reactive CTL with high affinity, limiting the successful development of antigen-specific immunotherapeutic strategies based on such tumor-reactive T cells. The aim of this project is the preclinical development of an adoptive immunotherapy against p53-positive tumors. The p53 tumor-suppressor protein is an antigen, which is markedly upregulated in multiple tumors. Such overexpression of p53 correlates with the presence of mutated variants of p53, which inactivate p53’s normal function as tumor-suppressor. Tumors with wildtype (wt) p53 also exhibit abnormalities in p53 expression, metabolism, and function, which arise from alterations of an impressive repertoire of p53-interacting gene products. Hence, perturbation of p53 regulatory pathways and metabolism occurs in most, if not all, types of human malignancies and makes class I MHC bound peptides naturally processed from the wt p53 protein almost universal targets for tumor-specific CD8+ CTL. The generation of CTL, bearing a high-affinity p53-specific T-cell receptor (TCR) reactive against such peptide/MHC-class I complexes presented on tumors, would display a promising strategy for cancer immunotherapy. Through adoptive transfer of autologous PBMCs, retrovirally transduced with genes encoding such TCR, self-tolerance against p53 in tumor patients could be circumvented leading to selective destruction of p53-expressing tumors without harming healthy tissue. Previous studies have described strategies to circumvent self-tolerance against p53 using HLA-A2.1 transgenic mice. Immunization of such mice with peptides derived from human p53 has generated efficient high-affinity p53A2.1-specific CTL clones. Moreover the TCR from one of these clones that specifically recognizes a wt p53 peptide (aa 264–272) could be cloned for the transduction into human T-cells. We could show that the introduction of this p53(264–272)A2.1-specific-TCR into human PBMCs via retroviral transduction produced effective and high affine T cells of high affinity capable of recognizing and lysing p53+ tumor cells while sparing normal p53-expressing cells. Apart from CD8+ T cells, p53(264–272)A2.1-specific-TCR-transduced CD4+ helper T cells (Th) too were able to recognize peptide-loaded p53(264–272)A2-complexes as well as p53/HLA-A2-positive tumor cells. Moreover both T cell subsets were cooperative and interacted synergistically with dendritic cell intermediates and tumor targets. The adoptive transfer of such gene-modified T cells could display a highly effective therapy against p53-positive tumors. To demonstrate the therapeutic potential of p53(264–272)/HLA-A2-specific TCR transgenic cells for a possible clinical translation, we have initiated preclinical studies for the adoptive transfer of such cells. Here, we demonstrate the function and safety in vitro and in vivo of a retroviral GMP-suitable vector construct coding for the p53(264–272)/HLA-A2-specific TCR designed for clinical application.

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Manufacture and Immunological Characterization of GMP-Compliant Functional Sars-COV-2 Cytotoxic T Lymphocytes (CTLs) Utilizing the Clinimacs ® Cytokine Capture System

Blood ◽

10.1182/blood-2021-145620 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 476-476

Author(s):

Yaya Chu ◽

Jordan Milner ◽

Margaret Lamb ◽

Elena Maryamchik ◽

Olivia Rigot ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

T Cell ◽

Board Of Directors ◽

Cd8 T Cells ◽

Research Funding ◽

Cytotoxic T Cell ◽

Advisory Committees ◽

Ifn Γ

Abstract Background: The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a pandemic that has taken millions of lives around the globe. Treatment of patients with moderate and severe COVID-19 disease has included dexamethasone, tocilizumab, Remdesivir, convalescent plasma, and targeted antibodies, however, currently, there are no FDA approved targeted cellular therapies in the treatment of mild or moderate SARS-CoV-2 disease. Virus-specific cytotoxic T cell lymphocytes (vCTLs) have shown therapeutic efficacy in immunocompromised patients with viral infections. We developed a multicenter and multidisciplinary Viral Cytotoxic T-Cell Consortium (VIRCTLC) to investigate the use of vCTLs manufactured by direct enrichment using the Cytokine Capture System (CCS) on the CliniMACS® Prodigy device. SARS-CoV-2 specific PepTivator Peptides consist of overlapping peptides that span the entire sequence of the protein (Protein N and M), or the length of its immunodominant domain (Protein S). The peptides can bind to either MHC class I or MHC class II molecules and are therefore able to target both CD4 and CD8 T cells. Objective: To screen, manufacture, and characterize SARS-CoV-2 vCTLs generated from convalescent COVID-19 donors using the CliniMACS® Cytokine Capture System on the CliniMACS® Prodigy device. Methods: Donor screening was done utilizing PBMNCs from 15 convalescent COVID-19 donors after informed consent. PBMNCs were stimulated with a mix of PepTivator peptides (Miltenyi Biotech®) contained in the S, M and N proteins. IFN-γ levels were examined in CD3, CD4, and CD8 T cells by flow cytometry analysis. After informed consent, PBMNCs from three convalescent COVID-19 donors who screened positively to the PepTivator® peptide pools of SARS-CoV-2 Proteins M, N and S were collected by apheresis using the SPECTRA Optia® apheresis instrument. PBMNCs were incubated with the PepTivator® peptide pools for 4 hours. After incubation, the SARS-CoV-2 vCTLs were enriched using the CliniMACS Cytokine Capture System as we have previously described (Flower/Cairo, et al, ASTCT, 2020). Samples were taken from the enriched vCTLs and tested in gram stains, sterility cultures, cell counts, viability and IFN-γ cytokine staining (CD3/CD4/CD8/IFN-γ marker panel) by flow cytometry. Amplification and sequencing of TCRβ CDR3 regions of pre-stimulated PBMNC, stimulated PBMNCs samples taken from the QC bag (QC samples) and the enriched SARS-CoV-2 vCTLs were performed on the ImmunoSEQ platform using ImmunoSEQ® TCRB Assay kit (Adaptive Biotechnologies, Seattle, WA, USA). Characterization of immune subsets was done by mass cytometry analysis with 41 Immunophenotypic markers. Transcriptome of the immune landscape of QC samples, and enriched vCTLs was compared with the pre samples using the human nCounter PanCancer Immune Profiling Panel on the nCounter system. Results: We demonstrate that 93.3% of convalescent donor blood samples passed the screening criteria for clinical manufacture. Three validation runs resulted in enriched T cells that consisted of 79% + 21% (mean + SEM) IFNγ + T cells (Fig.1). TCRβ sequencing showed that convalescent COVID-19 donors have a highly diverse TCR repertoire and we identified TCRβ CDR3 clones that are known to be associated with SARS-CoV-2 T cell responses. Immunophenotyping analysis demonstrated more CD4 T cells than CD8 T cells in the SARS CoV-2 vCTLs, an increase in memory CD8 and CD4 cells, especially CD8 T EM, CD4 T cm and CD4 T EMRA cells (Fig.2) and an increase DC cells in the SARS CoV-2 vCTL products as compared to pre-stimulated PBMNCs. Expression of the exhaustion markers was not enhanced in the SARS CoV-2 vCTLs as compared to pre-stimulated PBMNCs. Transcriptome analysis showed increased gene expression in T-cell function, interleukin, pathogen defense, and TNF superfamily pathway genes in the SARS CoV-2 vCTLs as compared to pre-stimulated PBMNCs. Conclusion: Our study demonstrates that highly functional SARS-CoV-2 vCTLs can be rapidly generated by direct cytokine enrichment from convalescent donor peripheral blood mononuclear cells. These data serve as pre-clinical validation for an ongoing clinical trial utilizing related HLA-matched and haplo-identical SARS CoV-2 vCTLs for the treatment of patients with mild and moderate SARS-CoV-2 disease (IND #27260, NCT# 04896606). Figure 1 Figure 1. Disclosures Lee: Kiadis Pharma: Divested equity in a private or publicly-traded company in the past 24 months, Honoraria, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Courier Therapeutics: Current holder of individual stocks in a privately-held company. Johnson: Miltenyi Biotec: Research Funding. Cairo: Jazz Pharmaceutical: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Speakers Bureau; Sanofi: Speakers Bureau; Servier: Speakers Bureau; Sobi: Speakers Bureau; Omeros: Membership on an entity's Board of Directors or advisory committees; Nektar: Membership on an entity's Board of Directors or advisory committees.

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524 Tim-4+ resident macrophages impair anti-tumor immunity in the serous body cavities By sequestering viable and cytotoxic CD8+ T cells expressing high levels of phosphatidylserine

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0524 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A560-A560

Author(s):

Andrew Chow ◽

Sara Schad ◽

Michael Green ◽

Matthew Hellmann ◽

Nicholas Ceglia ◽

...

Keyword(s):

Lung Cancer ◽

Flow Cytometry ◽

T Cells ◽

T Cell ◽

Peritoneal Carcinomatosis ◽

Tumor Cells ◽

Cd8 T Cells ◽

Cd8 T Cell ◽

Pleural Effusions ◽

Phosphatidylserine Receptor

BackgroundMalignant pleural effusions and peritoneal carcinomatosis are associated with poor outcomes in patients with cancer.1–3 Macrophages in these serous body cavities express the phosphatidylserine receptor Tim-4.4–8 Prior reports demonstrated that Tim-4 abrogation is associated with improved anti-tumor activity.9–11 Whether macrophages expressing Tim-4 contribute to immunosuppression in the serous body cavities has not been previously investigated.MethodsWe retrospectively annotated sites of metastases in 500 patients with lung cancer and assessed for clinical outcomes. Utilizing a combination of flow cytometry, immunohistochemistry, and antibody biodistribution assays, we surveyed for Tim-4 expression across various tissues and cell types. We performed flow cytometry on 55 consecutive pleural and peritoneal effusions from patients with lung cancer. We utilized murine models of peritoneal carcinomatosis to determine whether Tim-4 abrogation could enhance the anti-tumor efficacy of anti-PD-1 therapy. We characterized CD8+ T cells with high levels of phosphatidylserine (PShigh) with flow cytometry, cytotoxicity assays, and paired single cell RNA and TCR sequencing. Confocal microscopy was utilized to visualize interactions between Tim-4+ macrophages and PShigh CD8+ T cells.ResultsMetastatic disease involvement of the pleural or peritoneal cavity was associated with reduced response rate and progression-free and overall survival. We demonstrate that Tim-4 is highly expressed on pleural and peritoneal macrophages and other select resident macrophages, but not on monocytes, tumor-associated macrophages, or tumor cells in mice and humans. High levels of Tim-4 on macrophages from fluid biospecimens is associated with reduced levels CD39+ CD8+ T cells, which comprise the tumor-reactive portion of CD8+ T lymphocytes. In order to further elucidate the mechanism of Tim-4+ macrophage-mediated immunosuppression, we established a murine model of peritoneal carcinomatosis with MC38 and CT26 colon carcinoma. Genetic or pharmacologic abrogation of Tim-4 improved the efficacy of anti-PD-1 therapy and was associated with enhanced CD39+ CD8+ T cell numbers. In parallel, we observed in mice and humans that CD8+ T cell activation results in PS upregulation despite not undergoing cell death. PShigh CD8+ T cells expressed genes associated with cytotoxicity, activation/exhaustion, and proliferation, and mediated greater cytotoxicity. Mechanistic studies revealed that Tim-4 mediates sequestration of PShigh CD8+ T cells by macrophages which subsequently impedes CD8+ T cell cytotoxicity of tumor cells.Abstract 524 Figure 1After activation by antigen-presenting cells in the lymph nodes, viable CD8+ T cells express high levels of phosphatidylserine, which coincides with a highly proliferative and cytotoxic state. As they migrate towards tumors cells in the serous body cavities, they are sequestered by Tim-4+ resident macrophages which impede their anti-tumor cytotoxicity. Tim-4 abrogation can alleviate this sequestration and enhance anti-tumor immunityConclusionsWe demonstrate that Tim-4+ resident macrophages impair anti-tumor CD8+ T cell immunity in the serous body cavities and Tim-4 blockade represents on a novel therapeutic strategy to overcome resistance to immune checkpoint blockade (figure 1).Ethics ApprovalThe retrospective clinical analysis was approved by Memorial Sloan Kettering Cancer Center IRB #16-1566. The human biospecimen analyses were approved by Memorial Sloan Kettering Cancer Center IRB #06-107 and 14-091.ReferencesPorcel JM, et al., Clinical features and survival of lung cancer patients with pleural effusions. Respirology 2015;20:654–659.Donnenberg AD, Luketich JD, Dhupar R, Donnenberg VS. Treatment of malignant pleural effusions: the case for localized immunotherapy. J Immunother Cancer 2019;7:110.Morano WF, et al., Intraperitoneal immunotherapy: historical perspectives and modern therapy. Cancer Gene Ther 2016;23:373–381.Bain CC, et al., Long-lived self-renewing bone marrow-derived macrophages displace embryo-derived cells to inhabit adult serous cavities. Nat Commun 2016;7:ncomms11852.Wong K, et al., Phosphatidylserine receptor Tim-4 is essential for the maintenance of the homeostatic state of resident peritoneal macrophages. Proc Natl Acad Sci U S A 2010;107:8712–8717.Miyanishi M, et al., Identification of Tim4 as a phosphatidylserine receptor. Nature 2007;450:435–439.Rodriguez-Manzanet R, et al. T and B cell hyperactivity and autoimmunity associated with niche-specific defects in apoptotic body clearance in TIM-4-deficient mice. Proc Natl Acad Sci U S A 2010;107:8706–8711.Kobayashi N, et al. TIM-1 and TIM-4 glycoproteins bind phosphatidylserine and mediate uptake of apoptotic cells. Immunity 2007;27:927–940.LD Cunha et al. LC3-Associated phagocytosis in myeloid cells promotes tumor immune tolerance. Cell 2018;175:429–441 e416.Baghdadi M, et al, TIM-4 glycoprotein-mediated degradation of dying tumor cells by autophagy leads to reduced antigen presentation and increased immune tolerance. Immunity 2013;39:1070–1081.Baghdadi M, et al. Combined blockade of TIM-3 and TIM-4 augments cancer vaccine efficacy against established melanomas. Cancer Immunol Immunother 2013;62:629–637.

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549 Characterizing double positive T cells in the tumor microenvironment: a tale of promiscuous cell fates

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0549 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A586-A586

Author(s):

Sara Schad ◽

Andrew Chow ◽

Heng Pan ◽

Levi Mangarin ◽

Roberta Zappasodi ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Microenvironment ◽

Cd8 T Cells ◽

Human Melanoma ◽

B16 Melanoma ◽

T Cell Subsets ◽

Double Positive ◽

Cell Fates ◽

Single Positive

BackgroundCD4 and CD8 T cells are genetically and functionally distinct cell subsets of the adaptive immune system that play pivotal roles in immune surveillance and disease control. During development in the thymus, transcription factors ThPOK and Runx3 regulate the differentiation and maturation of these two lineages into single positive T cells that enter the periphery with mutually exclusive expression of either the CD4 or CD8 co-receptor.1–2 Despite our expectation that these two cell fates are fixed, mature CD4+CD8+ double positive (DP) T cells have been described in the context of numerous immunological responses, including cancer, but their molecular and functional properties and therapeutic relevance remain controversial and largely unknown.3–5MethodsOur lab has identified and characterized a heterogenous DP T cell population in murine and human melanoma tumors comprised of CD4 and CD8 T cells re-expressing the opposite co-receptor and a parallel uptake in the opposite cell type’s phenotype and function. Using CD4 (Trp1) and CD8 (Pmel) transgenic TCR T cells specific to B16 melanoma antigens gp75 and gp100 respectively, we demonstrate the re-expression of the opposite co-receptor following adoptive T cell transfer in B16 melanoma tumor bearing mice.ResultsSpecifically, up to 50% of transferred CD4 Trp1 T cells will re-express CD8 to become a DP T cell in the tumor microenvironment. Further, these CD4 derived DP T cells upregulate CD8 lineage regulator Runx3 and cytolytic genes Gzmb, Gzmk, and Prf1 to become potent cytotoxic T cells. Alternatively, a subset of CD8 Pmel T cells differentiate into DP T cells characterized by the increased expression of CD4, ThPOK, and regulatory marker FoxP3 (figure 1). In addition, we utilized 10x single cell and ATAC sequencing to further characterize these divergent DP T cell populations among open repertoire T cells isolated from murine and human melanoma tumors.ConclusionsOur findings highlight the capability of single positive T cells to differentiate in response to antigen and local stimuli into novel T cell subsets with polyfunctional characteristics. The resulting cell subsets will potentially affect the tumor microenvironment in distinct ways. Our studies may inform therapeutic approaches to identify antigen specific T cells as well as innovative signaling pathways to target when genetically engineering T cells to optimize cytotoxic function in the setting of adoptive cell therapy.Ethics ApprovalThe human biospecimen analyses were approved by Memorial Sloan Kettering Cancer Center IRB #06-107ReferencesEllmeier W, Haust L & Tschismarov R. Transcriptional control of CD4 and CD8 coreceptor expression during T cell development. Cell Mol Life Sci 2013;70:4537–4553.Luckey MA, et al. The transcription factor ThPOK suppresses Runx3 and imposes CD4+ lineage fate by inducing the SOCS suppressors of cytokine signaling. Nature Immunology 2014; 15, 638–645.Bohner P, et al. Double positive CD4(+)CD8(+) T Cells are enriched in urological cancers and favor T Helper-2 polarization. Front Immunol 2019; 10, 622.Nascimbeni M, Shin E-C, Chiriboga L, Kleiner DE & Rehermann B. Peripheral CD4(+)CD8(+) T cells are differentiated effector memory cells with antiviral functions. Blood 2004;104:478–486.Nishida K, et al. Clinical importance of the expression of CD4+CD8+ T cells in renal cell carcinoma. Int Immunol 2020;32:347–357.

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Quantitative assessment of the pool size and subset distribution of cytolytic T lymphocytes within human resting or alloactivated peripheral blood T cell populations.

Journal of Experimental Medicine ◽

10.1084/jem.158.2.571 ◽

1983 ◽

Vol 158 (2) ◽

pp. 571-585 ◽

Cited By ~ 84

Author(s):

A Moretta ◽

G Pantaleo ◽

L Moretta ◽

M C Mingari ◽

J C Cerottini

Keyword(s):

Monoclonal Antibody ◽

T Cells ◽

T Cell ◽

T Lymphocytes ◽

Peripheral Blood ◽

Great Majority ◽

T Cell Subsets ◽

Cytolytic T Lymphocytes ◽

Subset Distribution

In order to directly assess the distribution of cytolytic T lymphocytes (CTL) and their precursors (CTL-P) in the two major subsets of human T cells, we have used limiting dilution microculture systems to determine their frequencies. The two subsets were defined according to their reactivity (or lack thereof) with B9.4 monoclonal antibody (the specificity of which is similar, if not identical, to that of Leu 2b monoclonal antibody). Both B9+ and B9- cells obtained by sorting peripheral blood resting T cells using the fluorescence-activated cell sorter (FACS) were assayed for total CTL-P frequencies in a microculture system that allows clonal growth of every T cell. As assessed by a lectin-dependent assay, approximately 30% of peripheral blood T cells were CTP-P. In the B9+ subset (which represents 20-30% of all T cells), the CTL-P frequency was close to 100%, whereas the B9- subset had a 25-fold lower CTL-P frequency. It is thus evident that 90% and 10% of the total CTL-P in peripheral blood are confined to the B9+ or B9- T cell subsets, respectively. Analysis of the subset distribution of CTL-P directed against a given set of alloantigens confirmed these findings. CTL-P frequencies were also determined in B9+ and B9- subsets derived from T cells that had been activated in allogenic mixed leucocyte cultures (MLC). Approximately 10% of MLC T cells were CTL-P. This frequency was increased 3.5-fold in the B9+ subset, whereas the B9- subset contained only a small, although detectable number of CTL-P. Moreover, the great majority of the (operationally defined) CTL-P in MLC T cell population were found to be directed against the stimulating alloantigens, thus indicating a dramatic increase in specific CTL-P frequencies following in vitro stimulation in bulk cultures.

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644 Tumor-mediated suppressive signaling and hypoxia supports altered chromatin landscapes that limit the transcriptional and functional potential of terminal T cell exhaustion

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.644 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A673-A673

Author(s):

Rhodes Ford ◽

Natalie Rittenhouse ◽

Nicole Scharping ◽

Paolo Vignali ◽

Greg Delgoffe ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

T Cell ◽

Tumor Microenvironment ◽

Histone Modifications ◽

Cd8 T Cells ◽

Tumor Hypoxia ◽

T Cell Subsets ◽

T Cell Exhaustion ◽

Cell Exhaustion

BackgroundCD8+ T cells are a fundamental component of the anti-tumor response; however, tumor-infiltrating CD8+ T cells (TIL) are rendered dysfunctional by the tumor microenvironment. CD8+ TIL display an exhausted phenotype with decreased cytokine expression and increased expression of co-inhibitory receptors (IRs), such as PD-1 and Tim-3. The acquisition of IRs mark the progression of dysfunctional TIL from progenitors (PD-1Low) to terminally exhausted (PD-1+Tim-3+). How the chromatin landscape changes during this progression has not been described.MethodsUsing a low-input ChIP-based assay called Cleavage Under Targets and Release Using Nuclease (CUT&RUN), we have profiled the histone modifications at the chromatin of tumor-infiltrating CD8+ T cell subsets to better understand the relationship between the epigenome and the transcriptome as TIL progress towards terminal exhaustion.ResultsWe have identified two epigenetic characteristics unique to terminally exhausted cells. First, we have identified a unique set of genes, characterized by active histone modifications that do not have correlated gene expression. These regions are enriched for AP-1 transcription factor motifs, yet most AP-1 family factors are actively downregulated in terminally exhausted cells, suggesting signals that promote downregulation of AP-1 expression negatively impacts gene expression. We have shown that inducing expression of AP-1 factors with a 41BB agonist correlates with increased expression of these anticorrelated genes. We have also found a substantial increase in the number of genes that exhibit bivalent chromatin marks, defined by the presence of both active (H3K4me3) and repressive (H3K27me3) chromatin modifications that inhibit gene expression. These bivalent genes in terminally exhausted T cells are not associated with plasticity and represent aberrant hypermethylation in response to tumor hypoxia, which is necessary and sufficient to promote downregulation of bivalent genes.ConclusionsOur study defines for the first time the roles of costimulation and the tumor microenvironment in driving epigenetic features of terminally exhausted tumor-infiltrating T cells. These results suggest that terminally exhausted T cells have genes that are primed for expression, given the right signals and are the basis for future work that will elucidate that factors that drive progression towards terminal T cell exhaustion at the epigenetic level and identify novel therapeutic targets to restore effector function of tumor T cells and mediate tumor clearance.

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