Molecular and Functional Characterization of Gene Modified T Lymhocytes for Gene Therapy of Human Cancer

Abstract

Despite the tremendous evolution in tumor immunology and immunotherapy, adoptive immunotherapy still has a long way to go before it can be considered as a realistic therapeutic alternative for the treatment of cancer. One of the major problems encountered with the TIL immunotherapy is the availability of large quantities of tumor specific cytotoxic effector cells. Ex vivo expanded Tl L form a heterogeneous population, often exhibiting a low tumor specificity and/or cytotoxicity. The objective of this work was to explore, in an experimental in vitro system, the possibility to develop novel adoptive treatments for human breast cancer, based on the genetic modification of immune lymphocytes, by increasing their anti-tumor effector functions or anti-tumor specificity. In the first part of this thesis, the results are described of a set of experiments where human T lymphocytes were transfected with the cytokines TNF-a, IFN-y and IL-2 to increase their immunoreactivity against growing cancer cells. The main objective of this study was to evaluate the use of episomal eukaryotic expression vectors as an efficient expression system for human lymphoid cells. By using Epstein Barr virus (EBV)-derived episomal expression vectors, effector cells were generated, secreting high levels of these cytokines. In the second part, the construction, expression and functional characterization of a chimeric T cell receptor is described, composed of the Fv fragment of a mAb directed against a TAA expressed by the human mammary carcinoma cell line MCF7. By combining the fine specificity of this anti-tumor antibody with the effector functions of cytolytic T lymphocytes, a new type of effector cells with predefined specificity for MCF7 cells was generated.