Exploration of the Lysis Mechanisms of Leukaemic Blasts by Chimaeric T-Cells

Adoptive transfer of specific cytotoxic T lymphocytes (CTL) and Cytokine Induced Killer Cells (CIK) following genetic engineering of T-cell receptor zeta hold promising perspective in immunotherapy. In the present work we focused on the mechanisms of anti-tumor action of effectors transduced with an anti-CD19 chimaeric receptor in the context of B-lineage acute lymphoblastic leukemia (B-ALL). Primary B-ALL blasts were efficiently killed by both z-CD19 CTL and z-CD19 CIK effectors. The use of death receptor mediated apoptosis of target cells was excluded since agonists molecules of Fas and TRAIL-receptors failed to induce cell death. Perforin/granzyme pathway was found to be the mechanism of chimaeric effectors mediated killing. Indeed, cytolytic effector molecules perforin as well as granzymes were highly expressed by CTL and CIK. CD19 specific stimulation of transduced effectors was associated with degranulation as attested by CD107 membrane expression and high IFN-γ and TNF-α release. Moreover inhibitors of the perforin-based cytotoxic pathway, Ca2+-chelating agent EGTA and Concanamycin A, almost completely abrogated B-ALL blast killing. In conclusion we show that the cytolysis response of z-CD19 chimaeric effectors is predominantly mediated via perforin/granzyme pathway and is independent of death receptors signaling in primary B-ALL

L'espace de l'architecture moderne

La recherche vise à inventorier les éléments constitutifs générés par l'architecture du Mouvement moderne, d'en démontrer la validité contemporaine, de constituer un savoir afin de l'intégrer dans la pédagogie et la pratique du projet. Sont successivement analysés : la dette de l'architecture à la recherche picturale et le rôle de Théo van Doesburg, le travail de Mies van der Rohe sur l'extension horizontale de l'espace (pavillon de Barcelone) et celui de Le Corbusier sur l'extension spatiale ascendante (maison Cook, villa Meyer, villa Stein)

Transfert adoptif de lymphocytes T : Adoptive transfer of T lymphocytes

International audienceWithin a few years, the success of treatments based on the use of T-cells armed with a chimeric T-receptor for the CD19 molecule (CAR-T CD19) has revolutionized the perception of adoptive transfer approaches. The levels of responses observed in acute leukemias, of the order of 70-90 % are indeed unprecedented. The medical and financial enthusiasm aroused by these results has led to the current situation where more than 300 clinical trials are under way, against some thirty different antigens. This enthusiasm, well justified by the first successes, must however be tempered by the difficulties associated with the use of these cells. Indeed, the management of patients is made very complex both for medical reasons, because the toxicities associated with these treatments are important, and for technical reasons, because the preparation of T lymphocytes for therapeutic use requires dedicated structures. During this same period, knowledge of the mechanisms of regulation of T lymphocytes and the possibilities offered by synthetic biology and techniques of genome engineering have progressed considerably. Combined, they allow envisaging a true "programming" of the T lymphocytes, intended to improve the efficiency of the treatments and the safety of the patients. Medical and industrial perspectives and the role of these approaches in the arsenal of cancer therapies will depend largely on two conditions: the emergence of a robust demonstration of their effectiveness in solid tumors, and the establishment of an acceptable production and distribution model 1.En quelques années, le succès des traitements qui reposent sur l'utilisation de lymphocytes T armés d'un récepteur T chimérique pour la molécule CD19 (CAR-T CD19) a révolutionné la perception des approches de transfert adoptif. Les niveaux de réponses observés dans les leucémies aiguës, de l'ordre de 70–90 % sont en effet sans précédent. L'enthousiasme médical et financier suscité par ces résultats a conduit à la situation actuelle où plus de 300 essais cliniques sont en cours, contre une trentaine d'antigènes différents. Cet enthousiasme, bien justifié par les premiers succès, doit cependant être tempéré par les difficultés liées à l'utilisation de ces cellules. En effet, la prise en charge des patients est rendue très complexe à la fois pour des raisons médicales, parce que les toxicités associées à ces traitements sont importantes, et pour des raisons techniques, parce que la préparation de lymphocytes T pour un usage thérapeutique rend nécessaire la mise à disposition de structures dédiées. Pendant cette même période, la connaissance des mécanismes de régulation des lymphocytes T et les possibilités offertes par la biologie de synthèse et les techniques d'ingénierie du génome ont beaucoup progressé. Combinés, ils permettent d'envisager une véritable « programmation » des lymphocytes T, destinée à améliorer l'efficacité des traitements et la sécurité des patients. Des points de vue médical et industriel, la place que prendront ces approches dans l'arsenal des thérapies anticancéreuses dépendra en grande partie de deux conditions : l'émergence d'une démonstration robuste de leur efficacité dans les tumeurs solides, et la mise en place d'un modèle économique et de distribution acceptable

La Muscadine, histoire du pays. Madeleine. Bouteille du ménétrier. Par Henry Vié

Avec mode text

Transfection of FcγRIIIa (CD16) Alone Can Be Sufficient To Enable Human αβTCR T Lymphocytes To Mediate Antibody-Dependent Cellular Cytotoxicity

International audienceTo combine the immune potential of T cells and Ab therapy, we and others have previously shown that T cells transduction with a fusion receptor that binds the Fc portion of human Ig enable them to mediate Ab-dependent cellular cytotoxicity (ADCC). The fusion receptors previously described included the FcgRIIIa (CD16) receptor coupled to different chains intended to translate the signal. In this work, we questioned whether the transfection of CD16 alone into T human lymphocytes and NK cells could be sufficient for CD16 expression and function, or whether the cotransfection of a transducing chain was mandatory. Our results demonstrated that: 1) transfection of CD16 alone into a human NK cell line and primary T cells can be sufficient for CD16 expression and function; 2) cotransfection of CD3z or FceRIg increased CD16 expression; 3) yet this increased CD16 expression increased the ADCC score only for trastuzumab, not for rituximab or cetuximab; and 4) compared with that of peripheral NK cells, ADCC scores by autologous CD16-transfected T cells ranked differently according to the opsonized target cell. Together, these results showed that neither the use of a fusion receptor nor the cotransfection of a transducing chain is mandatory to transfer the ADCC function to human lymphocytes. Thus, depending on the effector/Ab/target combination considered, transfection of CD16 alone can be sufficient to enable T cells to mediate ADCC. In the context of immunotherapy, such a strategy is by nature safer than the use of a chimeric receptor, and is freely available

A high-performance, non-radioactive potency assay for measuring cytotoxicity: A full substitute of the chromium-release assay targeting the regulatory-compliance objective

International audienceStandardized and biologically relevant potency assays are required by the regulatory authorities for the characterization and quality control of therapeutic antibodies. As critical mechanisms of action (MoA) of antibodies, the antibody-dependent cell-meditated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) must be characterized by appropriate potency assays. The current reference method for measuring cytotoxicity is the 51Cr-release method. However, radioactivity handling is difficult to implement in an industrial context because of environmental and operator protection constraints. Alternative non-radioactive methods suffer from poor validation performances and surrogate assays that measure FcγR-dependent functions do not comply with the regulatory requirement of biological relevance. Starting from these observations, we developed a non-radioactive luminescent method that is specific for target cell cytolysis. In adherent and non-adherent target cell models, the ADCC (using standardized effector cells) or CDC activities of rituximab, trastuzumab and adalimumab were compared in parallel using the 51Cr or luminescent methods. We demonstrated that the latter method is highly sensitive, with validation performances similar or better than the 51Cr method. This method also detected apoptosis following induction by a chemical agent or exposure to ultraviolet light. Moreover, it is more accurate, precise and specific than the concurrent non-radioactive calcein- and TR-FRET-based methods. The method is easy to use, versatile, standardized, biologically relevant and cost effective for measuring cytotoxicity. It is an ideal candidate for developing regulatory-compliant cytotoxicity assays for the characterization of the ADCC, CDC or apoptosis activities from the early stages of development to lot release

Livres annoncés sommairement

Calmette Joseph, Galabert Fr., Leroux Alfred, Dutil Léon, Graillot Henri, Vié Louis. Livres annoncés sommairement. In: Annales du Midi : revue archéologique, historique et philologique de la France méridionale, Tome 26, N°102, 1914. pp. 294-309

Livres annoncés sommairement

Calmette Joseph, Galabert Fr., Leroux Alfred, Dutil Léon, Graillot Henri, Vié Louis. Livres annoncés sommairement. In: Annales du Midi : revue archéologique, historique et philologique de la France méridionale, Tome 26, N°102, 1914. pp. 294-309