Double Positive CD4CD8 αβ T Cells: A New Tumor-Reactive Population in Human Melanomas

BACKGROUND: Double positive (DP) CD4CD8 Talphabeta cells have been reported in normal individuals as well as in different pathological conditions including inflammatory diseases, viral infections and cancer, but their function remains to be elucidated. We recently reported the increased frequency of DP Talphabeta cells in human breast pleural effusions. This manuscript addresses the question of the existence and above all the role of this non-conventional DP sub-population among tumor associated lymphocytes in melanomas. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the intratumoral cell infiltrate in solid metastasis (n = 6) and tumor invaded lymph nodes (n = 26) samples from melanomas patients by multiparametric cytometry. Here we documented for the first time significant increased frequency of DP T cells in about 60% of melanoma tumors compared to blood samples. Interestingly, a high proportion of these cells produced TNF-alpha in response to autologous melanoma cell lines. Besides, they are characterized by a unique cytokine profile corresponding to higher secretion of IL-13, IL-4 and IL-5 than simple positive T cells. In deep analysis, we derived a representative tumor-reactive DP T cell clone from a melanoma patient's invaded lymph node. This clone was restricted by HLA-A*2402 and recognized both autologous and allogeneic tumor cells of various origins as well as normal cells, suggesting that the target antigen was a ubiquitous self antigen. However, this DP T cell clone failed to kill HLA-A*2402 EBV-transformed B cells, probably due to the constitutive expression of immunoproteasome by these cells. CONCLUSIONS/SIGNIFICANCE: In conclusion, we can postulate that, according to their broad tumor reactivity and to their original cytokine profile, the tumor associated DP T cells could participate in immune responses to tumors in vivo. Therefore, the presence of these cells and their role will be crucial to address in cancer patients, especially in the context of immunotherapies

Caracterisation phenotypique et fonctionnelle des lymphocytes de patients cancereux

SIGLEINIST T 71996 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Fonctions immunologiques de la molécule HLA-E ( implication en cancérologie et en tranplantation)

La molécule du CMH-I non classique HLA-E joue un rôle majeur dans le contrôle des réponses immunitaires à médiation cellulaire. Dans les conditions physiologiques, elle présente des peptides conservés du soi, et limite l'activation des cellules NK et T en interagissant majoritairement avec le récepteur NK inhibiteur CD94/NKG2-A. Cependant, lors de stress cellulaires, d'infections ou de la transformation tumorale, son répertoire peptidique peut varier générant ainsi de nouveaux complexes HLA-E-peptide susceptibles d'activer, de façon dépendante du TCR, des lymphocytes T. Dans cette étude, nous avons documenté l'alloréactivité de lymphocytes T CD8 restreints par la molécule HLA-E et induits lors de l'infection par le CMV chez un patient transplanté. Il apparaît que ces cellules T non conventionnelles sont capables de développer des réponses effectrices vis-à-vis de cellules endothéliales allogéniques in vitro, suggérant leur rôle délétère dans le cadre de transplantations d'organes solides vascularisé. Par ailleurs, nous avons montré que des cellules tumorales d'origines variées produisaient des formes solubles de la molécule HLA-E in vitro et que leur concentration était augmentée significativement dans le sérum des patients porteurs de mélanome. Ces résultats soulignent l'intérêt d'étudier la valeur pronostique des molécules HLA-E solubles chez les patients atteints d'un cancer. La caractérisation des propriétés fonctionnelles de ces formes solubles est en cours et permettra d'évaluer leur rôle dans divers contextes physiopathologiques.The non-classical MHC-I molecule HLA-E plays a major role in the control of cell-mediated immune responses. In physiological conditions, HLA-E molecules present self conserved peptides, and limit NK and T cells activation upon interaction with the inhibitory NK receptor CD94/NKG2-A. However, in times of cellular stress, infections or tumor transformation, their peptidome can be modified leading to the expression of new HLA-E-peptide complexes susceptible to be recognized, in a TCR dependent way, by T lymphocytes. In this study, we investigated the alloreactivity of CMV-committed HLA-E-restricted CD8 T lymphocytes isolated from a kidney transplant recipient. We demonstrated that these unconventional T cells are able to develop effective responses against allogeneic endothelial cells in vitro, suggesting their potential detrimental role upon solid organ transplantation. Moreover, we reported that soluble HLA-E molecules can be produced by tumor cells from various origins in vitro, and that their concentrations are significantly increased in melanoma patient sera. Therefore, these results address the potential prognostic value of soluble HLA-E molecules in cancer patients. The functional characterization of these molecules is in progress, in order to evaluate their role in various physiopathological contexts.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Les lymphocytes Tab CD4+CD8+ (de nouveaux acteurs de la réponse anti-tumorale dans le cancer du sein et le mélanome)

NANTES-BU Sciences (441092104) / SudocSudocFranceF

Adoptive transfer with high-affinity TCR to treat human solid tumors: how to improve the feasibility?

International audienceThe adoptive transfer of tumor antigen-specific T cells recently achieved clinical efficacy for a fraction of melanoma patients refractory to other therapies. Unfortunately , the application of this strategy to the remaining melanoma and most other cancer patients is hampered by the difficulty to generate high-affinity tumor-reactive T cells. Two strategies are currently developed to extend the feasibility of this therapeutic approach: clinical grade tool production for MHC-peptide multimer-driven sorting of antigen-specific T cells from the endogenous peripheral T cell repertoire and de novo engineering of the missing repertoire by genetic transfer of cloned specific T cell receptor (TCR) into T cells. The expected multiplication of adoptive transfer treatments, by these strategies, and their careful evaluation should enable the cure of a number of otherwise compromised cancer patients and to gain insight into the characteristics of transferred T cells best fitted to eradicate tumor cells, in terms of antigen specificities, phenotype, and functions. In particular, identification of tumor-rejection antigens by this approach would improve the design and efficacy of all immuno-therapeutic approaches

Editorial: Crosstalk between innate and adaptive immunity in colorectal cancer: Implications for immunotherapy

International audienceNo abstract availabl

Jotereau F: Suboptimal activation of melanoma infiltrating lymphocytes (TIL) due to low avidity of TCR/MHC-tumor peptide interactions

Coculture of melanoma cells and T cell clones derived from tumor-infiltrating lymphocytes (TIL) generally results in lysis of the antigen-bearing tumor cells but to inefficient proliferation and IL-2 secretion by responder T cells. This suboptimal activation is classically explained by an inability of tumor cells to provide costimulatory signals. Here we analyzed the responses to synthetic peptides of HLA-A2.1-restricted CTL clones specific for melanoma antigens MART-1 and NA17-A. We showed that peptide concentrations ranging from 1 pM to 10 nM efficiently sensitized the peptide transporter-deficient T2 cells to lysis. T2 cells pulsed with melanoma peptides also induced TIL proliferation and detectable secretion of IL-2, IFN-~/and GM-CSF, but only for peptide concentrations 10- to 10,000-fold higher than those required for lysis. Hence this suggests that partial triggering of TIL clones by melanoma cells could be due to expression of appropriate MHC-peptide complexes at subthreshold levels. In support of this, we showed that melanoma cells, unable to trigger IL-2 secretion, developed this ability when incubated with the appropriate peptide. These results indicate that the level of antigens expressed on melanoma tumors critically affects TIL activation status and thus, the efficiency of specific immune reactions mediated by these cells

High Proliferative Capacity and Specific Antiautologous Melanoma Cytotoxicity of a Human T-Lymphocyte Clone Derived from Tumor-Infiltrating Lymphocytes

International audienceA CD8+ clone, identified by its T-cell receptor gamma- and beta-gene configuration, was shown to preferentially develop, in the bulk culture of melanoma tumor-infiltrating lymphocytes with recombinant interleukin 2 after 1 month. Thirteen CD8+ clones were obtained by limiting dilution culture of tumor-infiltrating lymphocytes from 43-days old culture. Four of these clones, analyzed for T-cell receptor rearrangements, exhibited exactly the same T-cell receptor gene pattern as tumor-infiltrating lymphocytes from the bulk culture, showing, therefore, that all the CD8+ clones were subclones. All the 13 CD8+ subclones were strongly cytotoxic for autologous melanoma cells but did not kill K562. A more complete cytotoxicity analysis showed that the clones did not kill autologous fibroblasts or Con A blasts or allogeneic tumor targets. Furthermore, specific killing was inhibited by monoclonal antibodies against CD3, CD8, T-cell receptors alpha beta, and class I major histocompatibility complex antigens indicating that effector-to-target cell recognition was mediated through the T-cell receptor in a major histocompatibility complex-restricted fashion. These data showed that human melanoma-specific cytotoxic T lymphocytes can be obtained from melanoma TIL and that a single cytotoxic T lymphocyte clone can be expanded to more than 10(10) cells without a loss of autotumor specificity

Mécanismes physiopathologiques des effets secondaires des immunothérapies par anticorps anti-CTLA-4, anti-PD-1 et anti-PD-L1 dans le traitement du cancer

International audienceRecently, the emergence of anti-CTLA-4 and anti-PD-1/PD-L1 antibodies called immune check-point inhibitors (ICPI) has modified the landscape of anti-cancer treatments. These therapeutics are associated with immune related adverse events that affect many organs, most commonly skin, digestive tract, endocrine glands and lungs. This review summarizes the main physiopathological hypotheses on the mechanisms of these toxicities. In most cases, the T lymphocytes hyperactivation induced by ICPI generates a specific response directed against tumor antigens, leading to anti-tumor activity in tumor tissues but also side effects in normal tisues called “on-target”. The CD8+ cytotoxic T lymphocytes-mediated cell lysis induces the release of neoantigens, tumor antigens and auto-antigens from normal tissues, respectively. This phenomenon called “epitope spreading” leads to diversification of the T cell repertoire and thus to reduced immune tolerance, which is exacerbated by inhibition of regulator T lymphocytes. Furthermore, the predominant activation of Th1 and Th17T lymphocytes mediated by ICPI induced an increased production of pro-inflammatory cytokines such as interferon-γ (IFNγ) and interleukine-17 (IL-17). These two mechanisms are responsible for the so called “off-target” toxicities. The roles of cross-reactivity with the intestinal microbiota, hypersensitivity and the specific effect of PD-L2 remain to be determined. Better knowledge of these mechanisms will improve patient care and help predict patients at risk of developing severe toxicities to ICPIs.Ces dernières années ont vu l’essor de nouvelles immunothérapies anticancéreuses, notamment les inhibiteurs de check-points immunitaires (ICPI) visant à lever l’inactivation des lymphocytes T médiée par les récepteurs inhibiteurs CTLA-4, PD-1 et son ligand majoritaire PD-L1. Ces traitements sont associés à des effets secondaires immuns atteignant principalement la peau, le système digestif, les poumons et le système endocrine. Cette revue résume les principales hypothèses physiopathologiques de ces toxicités. La levée d’inhibition des lymphocytes T induite par les ICPI génère une réponse effectrice spécifique des antigènes de tumeur, responsable de l’activité antitumorale, mais également spécifique de ces antigènes présents dans les tissus non tumoraux à l’origine d’effets secondaires dits « on-target ». De plus, la lyse cellulaire médiée par les lymphocytes T CD8+ cytotoxiques dans la tumeur et dans les tissus sains libère des néo-antigènes, antigènes de tumeur et auto-antigènes respectivement. Ce phénomène dit d’« epitope spreading » conduit à une diversification du répertoire des lymphocytes T et à une diminution de la tolérance immunitaire périphérique accentuée par l’inhibition des lymphocytes T régulateurs. D’autre part, l’activation prédominante des lymphocytes T de type Th1 et Th17 induite par les ICPI génère la production de cytokines pro-inflammatoires, l’interféron γ et l’interleukine-17. Ces deux mécanismes génèrent une toxicité dite « off-target ». Le rôle de la cross-réactivité, de l’hypersensibilité et de PD-L2 restent à préciser. Une meilleure connaissance de ces mécanismes permettra d’améliorer la prise en charge des patients et de mieux identifier les populations à risque de toxicités sévères sous ICPI