Tumor-specific cytotoxic T cell clones from patients with breast and pancreatic adenocarcinoma recognize EBV-immortalized B cells transfected with polymorphic epithelial mucin complementary DNA.

Human breast and pancreatic adenocarcinomas are tumors of ductal epithelial cell origin and as such produce and express on their surface polymorphic epithelial cell mucin encoded by the MUC 1 gene. We have previously reported that tumor-specific cytotoxic T cells derived from patients bearing such tumors recognize specific epitopes on the mucin polypeptide core. This recognition was not MHC-restricted because of the highly repetitive sequence of the polypeptide core, which allows simultaneous recognition of many identical epitopes, and cross-linking and aggregation of TCR on mucin-specific T cells. Those studies were performed with limited numbers of tumor cells or allogeneic tumor cell lines. A renewable source of autologous cells presenting this Ag was necessary to further explore mucin-specific immunity. We report here successful establishment and functional analysis of mucin-specific CTL lines and clones derived from breast and pancreatic cancer patients, using either autologous or allogeneic mucin-transfected B cells as Ag. Our results demonstrate that transfection of autologous or allogeneic B cells with mucin confers upon them tumor Ag-presenting ability as well as susceptibility to lysis by mucin-specific CTL. Transfection of APC with this or any other human tumor Ag that may be molecularly defined in the future provides a unique and powerful tool with which to examine the ability of a tumor-associated Ag to stimulate T cell responses.