IL‐12 stimulation but not B7 expression increases melanoma killing by patient cytotoxic T lymphocytes (CTL)

Recent studies have demonstrated that rodent tumour cells engineered to secrete a variety of cytokines, or to express foreign antigens, MHC molecules or co‐stimulatory molecules, are rejected by syngeneic animals. These observations have led to the initiation of a number of clinical trials using genetically modified tumour cells, to attempt to stimulate a patient anti‐tumour immune response. In this study, a protocol has been developed to test in vitro the specific cytotoxic anti‐tumour response generated from melanoma patient lymphocytes. The results showed 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 used to design more appropriate genetically modified tumour vaccines.