Immunological perspectives into a naturally arising tumor

grantor: University of TorontoAlthough there is evidence that immune responses are induced against tumors, the development of cancer in patients suggests that tumor immunity is not efficient in vivo. In our model, immune responses to a naturally arising pancreatic $\beta$-islet cell tumor are examined. This spontaneously arising tumor has a defined viral tumor antigen to which responses against the tumor could be measured. Proliferation assays suggested the absence of an anti-tumor response. Activating the immune response via virus infection generated anti-tumor T-cells, but the response was not sustained. The animal's lifespan was prolonged by the manipulations, but failed to eradicate the disease. The tumor antigen specific T-cells were found not to be tolerant. Furthermore, continued expression of the tumor antigen was observed. Current immunotherapies of cancer involve tumor cells engineered to secrete cytokines. Since in our model there is a defined tumor antigen peptide, peptide therapy could be used to induce and sustain an anti-tumor response.M.Sc