Phenotypic Differences of CD103+ Tissue-Resident Memory T Cells Associated with Various Cancers

Pathobiology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Hye Seon Park ◽  
Yeonjin Jeon ◽  
Hyun Lee ◽  
Heejae Lee ◽  
Young-Ae Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Clinical Importance ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Clinicopathologic Characteristics ◽  
Phenotypic Differences ◽  
Cancer Types ◽  
Tumor Types ◽  
Resident Memory T Cells

<b><i>Background/Aims:</i></b> The presence and clinical importance of tissue-resident memory T (T<sub>RM</sub>) cells have been recently described in association with various cancer types. However, the frequency and the traditional naïve–effector–memory phenotypic characteristics of T<sub>RM</sub> cells are largely unknown. <b><i>Methods:</i></b> We analyzed single-cell populations of colorectal cancer (CC, <i>n</i> = 18), stomach cancer (SC, <i>n</i> = 13), renal cell carcinoma (RCC, <i>n</i> = 19), and breast cancer (BC, <i>n</i> = 16) by dissociation of tumor tissue with collagenase/hyaluronidase. We investigated populations of naïve, effector, and memory T and T<sub>RM</sub> cells by flow cytometry. <b><i>Results:</i></b> Among CD8<sup>−</sup> cells, CC was associated with a significantly higher proportion of CD103<sup>+</sup> T cells than other tumor types (<i>p</i> &#x3c; 0.001). Among CD8<sup>+</sup> cells, CC and SC were associated with higher CD103<sup>+</sup> T-cell proportions than RCC and BC (<i>p</i> &#x3c; 0.001). Significantly more CD8<sup>+</sup> than CD8<sup>−</sup> cells expressed CD103 (<i>p</i> &#x3c; 0.001). In association with SC, RCC, and BC, CD8<sup>+</sup> T cells had a similar T-cell phenotype composition pattern: fewer effector T cells and more memory-type T cells among CD103<sup>+</sup> cells compared with CD103<sup>−</sup> cells (<i>p</i> &#x3c; 0.05). Tumors with higher proportion of CD103<sup>+</sup> cells had no specific clinicopathologic characteristics than those with lower proportion of CD103<sup>+</sup> cells. <b><i>Conclusion:</i></b> T<sub>RM</sub> cell abundance and phenotypes varied among CC, SC, RCC, and BC. Further studies regarding the functional differences of T<sub>RM</sub> associated with various tumors are warranted.

Combination cancer immunotherapy targeting PD-1 and GITR can rescue CD8+T cell dysfunction and maintain memory phenotype

2018 ◽  
Vol 3 (29) ◽  
pp. eaat7061 ◽  
Author(s):  
Bei Wang ◽  
Wen Zhang ◽  
Vladimir Jankovic ◽  
Jacquelynn Golubov ◽  
Patrick Poon ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Programmed Cell Death ◽  
Cancer Immunotherapy ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Checkpoint Inhibition ◽  
Cell Dysfunction ◽  
T Cell Dysfunction

Most patients with cancer do not develop durable antitumor responses after programmed cell death protein 1 (PD-1) or programmed cell death ligand 1(PD-L1) checkpoint inhibition monotherapy because of an ephemeral reversal of T cell dysfunction and failure to promote long-lasting immunological T cell memory. Activating costimulatory pathways to induce stronger T cell activation may improve the efficacy of checkpoint inhibition and lead to durable antitumor responses. We performed single-cell RNA sequencing of more than 2000 tumor-infiltrating CD8+T cells in mice receiving both PD-1 and GITR (glucocorticoid-induced tumor necrosis factor receptor–related protein) antibodies and found that this combination synergistically enhanced the effector function of expanded CD8+T cells by restoring the balance of key homeostatic regulators CD226 and T cell immunoreceptor with Ig and ITIM domains (TIGIT), leading to a robust survival benefit. Combination therapy decreased CD8+T cell dysfunction and induced a highly proliferative precursor effector memory T cell phenotype in a CD226-dependent manner. PD-1 inhibition rescued CD226 activity by preventing PD-1–Src homology region 2 (SHP2) dephosphophorylation of the CD226 intracellular domain, whereas GITR agonism decreased TIGIT expression. Unmasking the molecular pathways driving durable antitumor responses will be essential to the development of rational approaches to optimizing cancer immunotherapy.

scholarly journals 368 Consistent pattern of immune activation induced by oncolytic adenovirus ONCOS-102 across diverse types of solid tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A396-A396
Author(s):  
Lukasz Kuryk ◽  
Anne-Sophie Moller ◽  
Sandeep Kumar ◽  
Alexander Shoushtari ◽  
Luis Paz Ares ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Solid Tumors ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Clinical Importance ◽  
Oncolytic Adenovirus ◽  
Link Type ◽  
Tumor Types

BackgroundSolid tumors exhibit highly variable compositions of immune infiltrates. Therapeutic compounds driving uniform remodeling of tumor microenvironment (TME) across tumor types may improve the efficacy of cancer immunotherapy. ONCOS-102, a granulocyte-macrophage colony stimulating factor (GM-CSF)-expressing oncolytic adenovirus (Ad5/3-D24-GMCSF), was tested for its safety, therapeutic efficacy and capacity to remodel TME in recently completed phase I/II clinical studies in anti-PD-1 refractory melanoma (NCT03003676) and malignant pleural mesothelioma (MPM) (NCT02879669).MethodsBiopsies were obtained from tumor lesions of patients treated with intra-tumoral injections of ONCOS-102 in combination with chemotherapy or pembrolizumab for MPM and melanoma, respectively. Tumor immune infiltrates were analyzed by immunohistology using several antibody panels. On-treatment biopsies were compared to paired baseline samples as wells as to samples from control patients treated with chemotherapy alone in the case of MPM. Gene expression data obtained by next generation RNA sequencing were used to complement the immunohistology analysis and all results were correlated to clinical outcomes.ResultsComparative TME analysis of anti-PD-1 refractory melanoma and MPM tumors revealed noticeably lower baseline T-cell infiltration in mesothelioma. Thus, fractions of CD8+ T-cells were significantly below 10% in 80% of MPM biopsies while approaching or exceeding this level in 60% of melanoma baseline samples. Comparison of tumor biopsies obtained at baseline or on-treatment, demonstrated increased infiltration by both CD4+ and CD8+ T-cells in large proportions of melanoma (CD4+: 13/20 (65%); CD8+: 16/19 (84%) and MPM (CD4+: 10/15 (67%); CD8+: 9/15 (60%) tumor lesions in response to ONCOS-102. Frequencies of cytotoxic T-cells with high granzyme-B expression also increased in response to the treatment in both tumor types, in particular when assessed as percentage of total CD8+ T-cells. Other observed changes induced by ONCOS-102 in samples taken from CR, PR and SD patients with MPM or melanoma included increased CD8/Treg ratio and modulation of PD-L1 expression. Biological and clinical importance of these findings was further supported by correlation between modulation of several subsets of genes related to the process of T-cell activation, such as cytotoxic granule components and co-stimulatory molecules, and clinical response to ONCOS-102 in melanoma and both tumor response and overall survival in MPM patients.ConclusionsONCOS-102 drives pro-inflammatory modulation of immune TME across tumor types of different origins, anatomical locations and immunological baseline characteristics. Our data support potential of ONCOS-102 to serve as a potent immune sensitizing agent in combination therapies with various classes of immunomodulatory compounds and chemotherapy.

scholarly journals The human liver microenvironment shapes the homing and function of CD4+T-cell populations

2020 ◽  
Author(s):  
Benjamin G. Wiggins ◽  
Laura J. Pallett ◽  
Xiaoyan Li ◽  
Scott P. Davies ◽  
Oliver E. Amin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Human Liver ◽  
Memory T Cells ◽  
T Cell Subsets ◽  
Cell Phenotype ◽  
List Type ◽  
Cd69 Expression ◽  
Resident Memory T Cells

ABSTRACTBackground & AimsTissue-resident memory T cells (TRM) are important immune sentinels that provide efficient in situ immunity. Liver-resident CD8+ TRM have been previously described, and contribute to viral control in persistent hepatotropic infections. However, little is known regarding liver CD4+ TRM cells. Here we profiled resident and non-resident intrahepatic CD4+ T cell subsets, assessing their phenotype, function, differential generation requirements and roles in hepatotropic infection.MethodsLiver tissue was obtained from 173 subjects with (n=109) or without (n=64) hepatic pathology. Multiparametric flow cytometry and immunofluorescence imaging examined T cell phenotype, functionality and location. Liver T cell function was determined after stimulation with anti-CD3/CD28 and PMA/Ionomycin. Co-cultures of blood-derived lymphocytes with hepatocyte cell lines, primary biliary epithelial cells, and precision-cut autologous liver slices were used to investigate the acquisition of liver-resident phenotypes.ResultsCD69 expression delineated two distinct subsets in the human liver. CD69HI cells were identified as CD4+ TRM due to exclusion from the circulation, a residency-associated phenotype (CXCR6+CD49a+S1PR1-PD-1+), restriction to specific liver niches, and ability to produce robust type-1 multifunctional cytokine responses. Conversely, CD69INT were an activated T cell population also found in the peripheral circulation, with a distinct homing profile (CX3CR1+CXCR3+CXCR1+), and a bias towards IL-4 production. Frequencies of CD69INT cells correlated with the degree of fibrosis in chronic hepatitis B virus infection. Interaction with hepatic epithelia was sufficient to generate CD69INT cells, while additional signals from the liver microenvironment were required to generate liver-resident CD69HI cells.ConclusionsIntermediate and high CD69 expression demarcates two discrete intrahepatic CD4+ T cell subsets with distinct developmental and functional profiles.Graphical AbstractHighlightsCD69HI (CXCR6+CD49a+S1PR1-PD-1+) are the CD4+ TRM of the human liverHepatic CD69INTCD4+ T-cells are distinct, activated, and recirculation-competentStimulation evokes respective IFN-γ and IL-4 responses in CD69HI and CD69INT cellsCD69INT cell frequencies correlate with worsening fibrosis in chronic HBV patientsLiver slice cultures allow differentiation of CD69INT and CD69HI cells from bloodLay summaryTissue-resident memory T cells (TRM) orchestrate regional immune responses, but much of the biology of liver-resident CD4+ TRM remains unknown. We found high expression of cell-surface protein CD69 defined hepatic CD4+ TRM, while simultaneously uncovering a distinct novel recirculatory CD69INT CD4+ T cell subset. Both subsets displayed unique immune receptor profiles, were functionally skewed towards type-1 and type-2 responses respectively, and had distinct generation requirements, highlighting the potential for differential roles in the immunopathology of chronic liver diseases.

scholarly journals Short-Lived Effector CD8 T Cells Induced by Genetically Attenuated Malaria Parasite Vaccination Express CD11c

2013 ◽  
Vol 81 (11) ◽  
pp. 4171-4181 ◽  
Author(s):  
Laura A. Cooney ◽  
Megha Gupta ◽  
Sunil Thomas ◽  
Sebastian Mikolajczak ◽  
Kimberly Y. Choi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Inflammatory Cytokines ◽  
Plasmodium Yoelii ◽  
T Cell Response ◽  
Parasite Development ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Effector Cells ◽  
Ifn Γ

ABSTRACTVaccination with a single dose of genetically attenuated malaria parasites can induce sterile protection against sporozoite challenge in the rodentPlasmodium yoeliimodel. Protection is dependent on CD8+T cells, involves perforin and gamma interferon (IFN-γ), and is correlated with the expansion of effector memory CD8+T cells in the liver. Here, we have further characterized vaccine-induced changes in the CD8+T cell phenotype and demonstrated significant upregulation of CD11c on CD3+CD8b+T cells in the liver, spleen, and peripheral blood. CD11c+CD8+T cells are predominantly CD11ahiCD44hiCD62L−, indicative of antigen-experienced effector cells. Followingin vitrorestimulation with malaria-infected hepatocytes, CD11c+CD8+T cells expressed inflammatory cytokines and cytotoxicity markers, including IFN-γ, tumor necrosis factor alpha (TNF-α), interleukin-2 (IL-2), perforin, and CD107a. CD11c−CD8+T cells, on the other hand, expressed negligible amounts of all inflammatory cytokines and cytotoxicity markers tested, indicating that CD11c marks multifunctional effector CD8+T cells. Coculture of CD11c+, but not CD11c−, CD8+T cells with sporozoite-infected primary hepatocytes significantly inhibited liver-stage parasite development. Tetramer staining for the immunodominant circumsporozoite protein (CSP)-specific CD8+T cell epitope demonstrated that approximately two-thirds of CSP-specific cells expressed CD11c at the peak of the CD11c+CD8+T cell response, but CD11c expression was lost as the CD8+T cells entered the memory phase. Further analyses showed that CD11c+CD8+T cells are primarily KLRG1+CD127−terminal effectors, whereas all KLRG1−CD127+memory precursor effector cells are CD11c−CD8+T cells. Together, these results suggest that CD11c marks a subset of highly inflammatory, short-lived, antigen-specific effector cells, which may play an important role in eliminating infected hepatocytes.

scholarly journals Protective Immunity against Experimental Pulmonary Cryptococcosis in T Cell-Depleted Mice

2011 ◽  
Vol 18 (5) ◽  
pp. 717-723 ◽  
Author(s):  
Karen L. Wozniak ◽  
Mattie L. Young ◽  
Floyd L. Wormley
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protective Immunity ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Cell Mediated Immunity ◽  
Wild Type ◽  
Pulmonary Cryptococcosis ◽  
Content Type ◽  
Immunocompetent Mice

ABSTRACTIndividuals with defects in T cell-mediated immunity (CMI) are highly susceptible to infection withCryptococcus neoformans. The purpose of these studies was to determine if protection against experimental pulmonary cryptococcosis can be generated in T cell-deficient hosts. BALB/c mice were depleted of CD4+and/or CD8+T cells or given an isotype control antibody prior to vaccination with aC. neoformansstrain, designated H99γ, previously shown to induce protection againstC. neoformansinfection in immunocompetent mice. Mice depleted of CD4+or CD8+T cells, but not both subsets, survived an acute pulmonary infection withC. neoformansstrain H99γ and a subsequent second challenge with wild-typeC. neoformansstrain H99. We observed a significant increase in the percentage of CD4+and CD8+T cells expressing the activation marker CD69 in the lungs of mice immunized withC. neoformansstrain H99γ prior to a secondary challenge with wild-type cryptococci. CD4+T cells within the lungs of immunized mice also appeared to acquire a predominantly activated effector memory cell phenotype (CD69+CD44+CCR7−CD45RB−CD62L−) following a second pulmonary challenge with wild-typeC. neoformans, compared to CD4+T cells from naïve mice. Lastly, immunization of immunocompetent mice withC. neoformansstrain H99γ prior to depletion of CD4+and/or CD8+T cells resulted in significant protection against a second challenge with wild-typeC. neoformans. Our studies demonstrate that protective immunity against pulmonary cryptococcosis can be generated in immunosuppressed hosts, thus supporting the development of cryptococcal vaccines.

scholarly journals Histone Acetyltransferase CBP Is Vital To Demarcate Conventional and Innate CD8+ T-Cell Development

2009 ◽  
Vol 29 (14) ◽  
pp. 3894-3904 ◽  
Author(s):  
Tomofusa Fukuyama ◽  
Lawryn H. Kasper ◽  
Fayçal Boussouar ◽  
Trushar Jeevan ◽  
Jan van Deursen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protein Tyrosine Kinase ◽  
Interleukin 2 ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Creb Binding Protein ◽  
Thymic Development ◽  
Nuclear Component ◽  
Single Positive

ABSTRACT Defining the chromatin modifications and transcriptional mechanisms that direct the development of different T-cell lineages is a major challenge in immunology. The transcriptional coactivators CREB binding protein (CBP) and the closely related p300, which comprise the KAT3 family of histone/protein lysine acetyltransferases, interact with over 50 T-lymphocyte-essential transcriptional regulators. We show here that CBP, but not p300, modulates the thymic development of conventional adaptive T cells versus those having unconventional innate functions. Conditional inactivation of CBP in the thymus yielded CD8 single-positive (SP) thymocytes with an effector-, memory-, or innate-like T-cell phenotype. In this regard, CD8 SP thymocytes in CBP mutant mice were phenotypically similar to those reported for Itk and Rlk protein tyrosine kinase mutants, including the increased expression of the T-cell master regulatory transcription factor eomesodermin (Eomes) and the interleukin-2 and -15 receptor beta chain (CD122) and an enhanced ability to rapidly produce gamma interferon. CBP was required for the expression of the Itk-dependent genes Egr2, Egr3, and Il2, suggesting that CBP helps mediate Itk-responsive transcription. CBP therefore defines a nuclear component of the signaling pathways that demarcate the development of innate and adaptive naïve CD8+ T cells in the thymus.

scholarly journals Application of a Standardized Flow Cytometry Panel for Defining and Monitoring the Immunophenotype of CAR-T Cells

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5626-5626
Author(s):  
Irene Scarfò ◽  
Kathleen Gallagher ◽  
Marcela V. Maus ◽  
Rebecca Larson ◽  
Maegan Sheehan ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Unmet Need ◽  
Central Memory ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Memory T Cell ◽  
Car T

Chimeric antigen receptor T-cells (CAR-T) have emerged as an extremely promising therapy for hematological malignancies. The immunophenotype of apheresis material and the CAR-T cell product is known to be predictive of the likelihood of response to treatment of certain malignancies. Central memory and stem cell-like memory T cell phenotypes are associated with a more sustained proliferative response and long-term CAR-T persistence (Fraietta et al, Nature Medicine, 2018). There is an unmet need for standardized methods and reagents to reliably profile the memory phenotype of CAR-Ts to better evaluate product quality, and support improvements in CAR-T manufacturing. The BD Biosciences dried memory T-cell panel contains a pre-validated mixture of 7 antibodies for the identification of naïve, stem cell memory, central memory and effector memory CD4+ and CD8+ T cell subsets. The pre-mixed dried antibody tube offers consistency in staining profiles over time and reduces the risk of operator errors. Additional drop-in antibodies can complement the panel and enable more in-depth evaluation of the T cell phenotype. Here we demonstrate the use of this panel with drop-in markers to monitor changes in expression of PD-1, TIM-3, LAG-3, HLA-DR, CD45RO, and CXCR3 on T cells transduced to express our novel anti-CD37 CAR. Cells were stained at day 0 prior to transduction, day 7, and following resting and re-stimulation, and acquired on a 12 color BD FACS Lyric. The use of a standardized memory T-cell panel will allow us to more accurately evaluate how T-cell phenotype impacts on the efficacy and longevity of response in patients receiving CAR-T therapies. Disclosures Maus: INFO PENDING: Other: INFO PENDING. Bornheimer:BD Biosciences: Employment. Hanley:BD Biosciences: Employment. Frigault:Novartis: Patents & Royalties: Royalty; Arcellx, Celgene, Foundation Medicine, Kite/Gilead, Nkarta, Novartis, and Xenetic: Consultancy.

scholarly journals Persistent memory CD4+ and CD8+ T-cell responses in recovered severe acute respiratory syndrome (SARS) patients to SARS coronavirus M antigen

2007 ◽  
Vol 88 (10) ◽  
pp. 2740-2748 ◽  
Author(s):  
Litao Yang ◽  
Hui Peng ◽  
Zhaoling Zhu ◽  
Gang Li ◽  
Zitong Huang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Severe Acute Respiratory Syndrome ◽  
Flow Cytometric Analysis ◽  
Memory Cell ◽  
T Cell Response ◽  
M Protein ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Human T Cell

The membrane (M) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) is a major glycoprotein with multiple biological functions. In this study, we found that memory T cells against M protein were persistent in recovered SARS patients by detecting gamma interferon (IFN-γ) production using ELISA and ELISpot assays. Flow cytometric analysis showed that both CD4+ and CD8+ T cells were involved in cellular responses to SARS-CoV M antigen. Furthermore, memory CD8+ T cells displayed an effector memory cell phenotype expressing CD45RO− CCR7− CD62L−. In contrast, the majority of IFN-γ + CD4+ T cells were central memory cells with the expression of CD45RO+ CCR7+ CD62L−. The epitope screening from 30 synthetic overlapping peptides that cover the entire SARS-CoV M protein identified four human T-cell immunodominant peptides, p21-44, p65-91, p117-140 and p200-220. All four immunodominant peptides could elicit cellular immunity with a predominance of CD8+ T-cell response. This data may have important implication for developing SARS vaccines.

scholarly journals Expression of Senescence Marker TIGIT Identifies Polyfunctional Donor-Reactive CD4+ T Cells Preferentially Lost After Kidney Transplantation

2021 ◽  
Vol 12 ◽  
Author(s):  
Amy C. J. van der List ◽  
Nicolle H. R. Litjens ◽  
Mariska Klepper ◽  
Michiel G. H. Betjes
Keyword(s):  
T Cells ◽  
Kidney Transplantation ◽  
T Cell ◽  
Expression Profile ◽  
Cd4 T Cells ◽  
Effector Memory ◽  
Cell Phenotype ◽  
Kidney Transplant Recipients ◽  
Post Transplantation ◽  
Cytokine Expression Profile

Development of T-cell hyporesponsiveness to donor antigen may explain the substantial decreased risk for acute rejection in the years following kidney transplantation. The underlying mechanisms of donor-specific hyporesponsiveness (DSH) are largely unknown but may allow for lowering of immunosuppressive medication. Due to the onset of DSH being more rapid and pronounced in older recipients (+55 years), we hypothesized that immunosenescence/exhaustion of T lymphocytes would be a contributing factor. This study tested whether donor-reactive recipient T cells become hyporesponsive due to exhaustion from continuous stimulation by donor antigen. Circulating donor-reactive T cells of both young and elderly stable kidney transplant recipients (N=17) before and 3-5 years after transplantation were analyzed at the single cell level for expression of exhaustion markers by multi-parameter flow cytometry followed by unsupervised and unbiased clustering. Clusters containing cells of a particular expression profile with significant differential abundance after transplantation were identified and further analyzed. Unexpectedly, our results do not demonstrate an increase in exhausted donor antigen-reactive T cells post transplantation. Instead, we demonstrate a significant decrease in donor antigen-reactive CD4+ T cells expressing T cell immunoglobulin and ITIM domain (TIGIT) long after transplantation. Further analysis at earlier timepoints indicated that this decrease is already present at six months post transplantation. Characterization of these CD4+ T donor-reactive cells expressing TIGIT revealed them to have a predominantly central and effector memory T cell phenotype and a highly poly-functional cytokine expression profile. This study has therefore identified TIGIT as a marker for a previously undescribed polyfunctional donor-reactive CD4+ T cell population whose decline following kidney transplantation may explain development of DSH.

Marrow-Infiltrating T Cells In Patients with Chronic Lymphocytic Leukemia Display Markers of Functional Impairment and Express PD-1

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2417-2417
Author(s):  
Ursula Hainz ◽  
Quinlan L. Sievers ◽  
Kristen Stevenson ◽  
Natalie R. Goldstein ◽  
David Dorfman ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Chronic Lymphocytic Leukemia ◽  
Regulatory T Cells ◽  
Cd8 T Cells ◽  
Immunohistochemical Staining ◽  
Conflicts Of Interest ◽  
Lymphocytic Leukemia ◽  
Effector Memory ◽  
Cell Phenotype

Abstract Abstract 2417 Marrow is a major site of disease development and progression for chronic lymphocytic leukemia (CLL), as well as a priming site for antigen-specific T cells and a reservoir for memory T cells. To determine the extent to which T cells in the marrow microenvironment have an altered phenotype and function in CLL, we analyzed the immunophenotypic characteristics of marrow-infiltrating T cells of 18 CLL patients compared to 11 normal donors. Chemotherapy-naïve CLL patients (n=7) possessed comparable quantities of marrow T cells compared to normal donors (median CD8+ T cells/μl = CLL 904 vs normal 1247; median CD4+ T cells/μl = CLL 1975 vs normal 1110). However, we identified several aberrant characteristics among T cells infiltrating the marrow of CLL patients. First, the ratio of CD8+ to regulatory T cells (CD4+CD25+FOXP3+) was depressed (median ratio CLL 14 vs normal 41), indicating more regulatory T cells per effector T cells in CLL. Second, compared to normal marrow T cells, CLL marrow contained proportionally fewer functional effector CD8+ T cells (CD27+CD28+)(median normal 57%, CLL 48%) and more immunosenescent cells (CD27-CD28-)(median normal 21%, CLL 30%). Third, the T cell differentiation state of CLL CD8+ T cells was skewed to favor a phenotype of increased terminal differentiation (CD45RA+CCR7-)(median CLL 55% vs normal 40%), and decreased naïve (CD45RA+CCR7+) cells (median CLL 21% vs normal 31%) compared to normal donors. These differences were further accentuated in CLL samples collected within 4 months from treatment with conventional chemotherapy (n=11). Finally, by immunohistochemical staining of CLL marrow biopsies, we observed marrow-infiltrating lymphocytes to express PD-1 (mean of infiltrating T cells, untreated CLL 12%, treated CLL 35%, present even >6 months after therapy), a marker associated both with immuno-activation and inhibition. While the majority of PD-1+ CD8 T cells of normal donors (n=5) and treated CLL patients (n=4) were differentiated towards effector memory (CD45RA-CCR7-) cells (median normal 46% vs untreated CLL 16%, p=0.07; treated CLL 61%), the PD-1+ T cells from untreated CLL patients (n=5) were terminally differentiated (CD45RA+CCR7+)(median normal 23% vs untreated CLL 65%, p=0.04; treated CLL 24%). These results indicate an exhausted rather than an activated T cell phenotype in untreated patients. Paired immunophenotypic analysis on blood and marrow from the same individuals (n=9) demonstrated an increased percentage and intensity of PD-1 expression on T cells from marrow compared to blood (percentage CD8+ T cells BM vs blood p = 0.05). Interestingly, PD-1 was also detected on CLL cells (n=16) but not normal B cells (median normal 0%, vs CLL 17%, p = 0.004). The ligand for PD-1, PD-L1, was detected in the marrow vasculature by immunohistochemical staining of biopsies, suggesting that the marrow microenvironment plays a role in the induction of PD-1 associated immunosuppression. Ligation of blood PD-L1 on CLL-T cells led to a 2-fold decrease in activation (measured as CD69 expression) of CD3/CD28 stimulated patient T cells. In summary, we identify several phenotypic and functional alterations within marrow-infiltrating T cells of CLL patients. We speculate these together may contribute to impaired priming of host immunity against the tumor. The PD-1 pathway appears to be activated in CLL, especially in the setting of chemotherapeutic treatment. Since anti-PD1 antibodies are now clinically available, it may be possible to target this pathway to improve anti-tumor responses. Disclosures: No relevant conflicts of interest to declare.

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