Human pancreatic cancer cells (MPanc-96) recognized by autologus tumor-infiltrating lymphocytes after in vitro as well in vivo tumor expansion

A human tumor line designated MPanc-96 has been established from a poorly differentiated primary pancreatic adenocarcinoma, MPanc-96 has a doubling time of 27 hr and grows as a confluent monolayer in various culture media. Cytogenetic analysis of in vitro-cultured tumor cells revealed a large number of clonal chromosomal aberrations, confirming their neoplastic origin, MPanc-96 grows in SCID mice when injected s.c. Xenografts established from the tumor line had a similar histology as the primary tumor. Tumor-infiltrating lymphocytes (TILs) were isolated from the primary tumor, and cytotoxic T lymphocytes (CTLs) were generated after activation on immobilized anti-CD3 monoclonal antibody (MAb) for 48 hr, expansion in low-dose IL-2 and repeated stimulation with irradiated MPanc-96 tumor cells. The generated CTLs lysed fresh autologous tumor cells as well as in vitro and in vivo expanded tumor cells from passages 9-53, suggesting that one or more tumor-associated antigens (TAAs) are stably expressed, CTLs lysed tumor cells in an HLA-class I-restricted fashion but showed no significant cytotoxicity against autologous fibroblasts, several allogeneic pancreatic cancer cell lines or K562. Our findings may be significant for the design of an animal model for studying the mechanisms of immunotherapy in human pancreatic cancer or for the identification of TAAs in pancreatic cancer.