IL-12 STIMULATION BUT NOT B7 EXPRESSION INCREASES MELANOMA KILLING BYPATIENT CYTOTOXIC T-LYMPHOCYTES (CTL)

Recent studies have demonstrated that rodent tumour cells engineered t o secrete a variety of cytokines, or to express foreign antigens, MHC molecules or co-stimulatory molecules, are rejected by syngeneic anima ls. These observations have led to the initiation of a number of clini cal trials using genetically modified tumour cells, to attempt to stim ulate a patient anti-tumour immune response. In this study, a protocol has been developed to test in vitro the specific cytotoxic anti-tumou r response generated from melanoma patient lymphocytes. The results sh owed that IL-12 in combination with IL-2 enhanced the autologous anti- melanoma CTL response, whereas B7.1 antigen expression on tumour cells did not increase anti-melanoma CTL generation. This method could be u sed to design more appropriate genetically modified tumour vaccines.