Growth Inhibition of Murine Colonic Adenocarcinoma by Tumor Immune but not by IL-2-Activated or Alloactivated Lymphocytes

Abstract

The antigenic profile of C-26 and C-51 BALB/c colonic adenocarcinomas was examined by in vivo and in vitro assays. Mice immunized with irradiated C-26 or C-51 tumor cells from freshly excised tumor nodules or from in vitro-growing cell lines were able to reject a challenge of both tumors. Spleen lymphocytes of immune but not of normal mice were effective in cross-inhibiting tumor growth in vivo in a Winn assay. Tissue-associated antigens common to C-26 and C-51 and to their metastases but not to other syngeneic neoplasms were detected in vitro by cytotoxic T lymphocytes obtained after 5 days of a secondary culture of immune lymphocytes and irradiated tumor cells. Activated lymphocytes were obtained by exposure of spleen cells to interleukin 2 or by allostimulation. Such lymphocytes, although cytotoxic in vitro on C-26 and C-51 carcinomas, were unable to significantly reduce in vivo tumor growth in the Winn assay.