Expansion and characterization of T cells transduced with a chimeric receptor against ovarian cancer

Adoptive immunotherapy with genetically modified T lymphocytes is being uti lized in clinical trials for the treatment of a broad range of diseases inc luding cancer and HIV infection. To improve on these treatments, and to bet ter understand their mechanisms of action, it is necessary to develop techn iques to generate large numbers of cells and characterize the functional he terogeneity of the cells produced. In this study, patient peripheral blood lymphocytes were transduced with a chimeric antigen receptor (MOv-gamma) de rived from a mouse monoclonal antibody against folate-binding protein, whic h is overexpressed on many ovarian cancers. Thus, irrespective of their ori ginal specificity, normal human T lymphocytes were redirected to react agai nst ovarian cancer cells. Lymphocytes from five patients were transduced an d grown to large numbers, with a median expansion of more than 7000-fold. W hen proliferation was inadequate, the cells were expanded by stimulation ut ilizing anti-CD3, IL-2, and irradiated allogeneic PBMCs. The cells maintain ed their functional ability to recognize ovarian cancer over several months . Cloning of transduced cells was undertaken to determine the level of gene expression and function of individual cells making up the bulk population. Transduced CD4(+) and CD8(+) cell clones were isolated from the bulk and d emonstrated antitumor activity. These clones had a diverse repertoire with respect to secretion of cytokines, and individual clones maintained their c ytokine profile on subsequent expansion. These studies establish the feasib ility of consistently generating large numbers of gene-modified tumor-react ive lymphocytes, with a stable and diverse cytokine repertoire, that could be utilized for patient treatment.