Experiments evaluating antitumor immunity induced by cholesterol hemisuccinate-treated syngeneic cell vaccines

Evaluation of the efficiency of immunizations with syngeneic tumor vaccines prepared from cells treated with cholesterol hemisuccinate (CHS) was performed in five animal models: P815 mastocytoma in DBA/2 mice, MCA-103 fibrosarcoma in C57BL/6N mice, L1210 leukemia in DBA/2 mice, Ehrlich ascites carcinoma in C57BL/6N mice, and CBP pancreatic cancer in CB/SsLak hamsters. Animals received two to four weekly intraperitoneal immunizations with 10(6) or 10(7) tumor cells, followed by challenges with syngeneic viable tumor cells. Survival and tumor growth rates were observed. No significant differences were observed among animals immunized with CHS-treated irradiated tumor vaccines, nontreated irradiated tumor vaccines, and nonimmunized controls in the P815, MCA-103, L1210, and CBP models. Mice immunized with nontreated irradiated Ehrlich ascites cell vaccines showed longer survival than those immunized with CHS-treated irradiated cell vaccines and nonimmunized controls. Results indicated that CHS-treated tumor cell vaccines were not effective in protecting against tumor challenges in five different syngeneic tumor models.