WP2. Innovative cellular immunotherapies
Two complementary projects are proposed within this WP in order to design cellular immunotherapies with enhanced efficacy. Project P4 will aim at implementing clinical grade protocols for sorting, in vitro expansion and functional differentiation of adoptively transferred T cells and dendritic cells , through implementation of several clinical grade approaches for sorting Ag‐specificTcells, optimization of T and DC expansion and polarization protocols using GMP grade cytokines. New approaches for in vivo follow up of the fate (survival, homing) of transferred cells will be worked out within project P5, through assessment of cell labeling protocols with enhanced sensitivity and reduced toxicity.
Task 4 – Cell therapies
Task 4.1 « Cell Immunotherapy »
T 4.1.1 Optimization of specific cytotoxic T lymphocytes (CTL) in vitro selection/amplification for therapeutic protocols.
Teams involved in the program : E1 + E2 Inserm U892
Participants Team 1 : H. Vié, B. Clémenceau,
Participants Team 2 : N. Labarrière, S. Simon, V. Vignard
Although adoptive transfer of antigen-specific T cells has now a history of two decades marked by encouraging results, its potential remains largely unexplored. One of the numerous difficulties that impeded a definite analysis of their interest was the way the T cells were selected in vitro, that until recently allowed only a poor knowledge of the composition of the T cell repertoires transferred into the patients. During the past two decades, increased knowledge of the viral and tumor antigens as well as the emergence of new methods for T cell selection based allowed the development of T cell selection and amplification procedures for adoptive immunotherapy.
The objectives of the project are to compare and optimize these enrichment methods for various T cell epitopes (derived from glioblastoma and melanoma antigens), in terms of amplification efficiency and purity yields, and also in terms of functionality of specific T cells, with particular attention paid to molecules involved in T cell inhibition.
T 4.1.2 Glioblastoma immunotherapy : a model for the use of banked allogeneic T cells
Team leader is CRCNA Team 1 (H. Vié, B. Clémenceau, E. Scotet and M. Bonneville),
in association with: CRCNA Teams 6 and 14, the Département de Neurochirurgie, University Hospital, Angers and CNRS UMR 6061, IGDR, Rennes.
The prognosis of glioblastoma multiform (GBM) patients with malignant brain tumor is dismal which justifies an urgent need for developping novel effective treatments. Previous studies indicate that the adoptive transfer of cellular cytotoxic effectors of the immune system, within the tumor resection cavity, represents a suitable strategy for a specific eradication of tumor cell targets in GBM. To this end, these cellular effectors with defined specificities, need to be selected and enriched from allogeneic healthy donor blood samples, expanded ex vivo and banked before the clinical assay (check fig. below). The main objective of this preclinical program is to bring arguments for justifying and prioritizing cellular immunotherapies targeting various effector cell subsets candidates for the treatment of GBM patients. This program will be developped in three complementary experimental systems. 1) in vitro comparison of the different cellular strategies of GBM tumor cell targeting, 2) ex vivo analysis by videomicroscopy of the dynamics and response of human effector cells into viable slices of GBM tumors and, 3) xenografts of human GBM tumors in mice after stereotaxic injection of GBM cells to assess in vivo the feasibility and antitumor efficacy of the previously selected immunotherapeutic strategies. This program adresses fundamental issues, dealing with human effector T cells handling, their activation modalities, as well new technological developments (eg, videoimaging, mouse model). From a therapeutic standpoint, the results of this preclinical project should provide insights into the feasibility, the safety and the efficacy of cellular immunotherapy strategies for the treatment of GBM tumor patients.
Task 4.2 “Optimization of cell therapy protocol using tolerogenic dendritic cells in transplantation”
The use of immunosuppressive drugs to treat transplant recipients has markedly reduced the incidence of acute rejection and early graft loss. However such treatments have numerous adverse side effects and have failed to prevent chronic allograft dysfunction. In this context, therapies based on the adoptive transfer of regulatory cells are promising strategies to induce indefinite transplant survival. Use of tolerogenic dendritic cells (DC) appears to be a good candidate as preliminary experiments done in rodents showed that administration of tolerogenic DC prolong graft survival. In this context, we are part in a European program called the “One Study” in which the safety of different immunoregulatory cell products in organ transplantation recipients will be tested (Phase I/II clinical trial). In our center, tolerogenic dendritic cells will be injected in humans as described in the scheme below.
The standard description of TolDC based on their phenotype, their own function (maturation resistance) and also their function on T cells (hypostimulation and suppression of T cells) was performed and necessary to use these cells in a clinical trial.
We are now working on an in-depth characterization on these TolDC to further understand their mechanisms of action. These experiments include a precise analysis of the molecules highly expressed by TolDC which were highlighted by microarrays technique. In parallel, in collaboration with the platform of humanized rodents, we also investigate the survival and the migration of TolDC after injection in humanized mice. Furthermore, the efficacy of TolDC in these animals to prevent GVHD development is also studied.
The in-depth characterization of TolDC is essential before considering a Phase II clinical trial using these cells in which the efficacy of TolDC will be evaluated.
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