ADOPTIVE IMMUNOTHERAPY UTILIZING T CELLS INDUCED BY GENE MODIFIED HUMAN CANCERS

虽然实验已经很好地证实了这种转移

Although it has been well established experimentally that the transfer of sensitized T lymphocytes can mediate potent antitumor effects, extrapolating the principles of adoptive immunotherapy obtained from animal studies to clinical therapy will require the development of innovative techniques to isolate and propagate antitumor effector T cells from cancer patients. Toward this end, we have established culture methods whereby cells from tumor-draining or tumor primed lymph nodes (LN) can be sensitized to acquire therapeutic efficacy. Since these cells do not demonstrate overt antitumor reactivity before culture, they are functionally referred to as "pre-effector" cells. One method involves the in vitro sensitization (IVS) of pre-effector cells with tumor cells in the presence of IL-2. Another method involves the sequential activation of pre-effector LN cells with anti-CD3 mAb followed by expansion in low concentrations of IL-2. In preliminary clinical studies, we have demonstrated the feasibility of inducing vaccine primed LN cells by the in vivo inoculation of autologous tumor cells admixed with BCG followed by in vitro activation by the methods described. DTH responsiveness to autologous tumor was conferred by the adoptive transfer of activated cells; and tumor regression was evident in a select group of patients. Major obstacles which confront the clinical applications of adoptive immunotherapy include the relatively poor immunogeneicity of human cancers and the potential problems of tumor-induced immunosuppression. Recent observations in animal studies indicate the tumors can be genetically altered to enhance the host immune response against native or parental tumor antigens. The transfection of tumor cells with specific cytokine genes have resulted in T cell mediated rejection of these tumors by their syngeneic hosts. In a different approach, we have found that the transfection of murine tumor cells by an allogeneic MHC class I gene will upregulate pre-effector cell sensitization against the poorly immunogenic B16BL6 melanoma; abrogate tumor-induced suppression of pre-effector cell induction; and can mediate regression of large established tumors by a novel in vivo transfection technique. These observations provide an impetus for the design of a clinical protocol examining the efficacy of gene-modified tumors utilized as a vaccine to induce pre-effector LN cells in cancer patients for subsequent adoptive immunotherapy. The specific aims of the current proposal are: (1) TO conduct a clinical trial of adoptive T cell immunotherapy with anti- CD3/IL-2 activated LN cells induced by the inoculation of gene-modified tumor cells, (2) To assess the toxicity, antitumor efficacy, in vivo immunological reactivity of patients, and in vivo homing of the activated cells, and (3) To characterize the in vitro antigen specificity of the sensitized T cells, and investigate methods of optimal sensitization of T cells utilizing cytokines and/or anti-CD28 mAb.