Activation of cytotoxic T cells by nonstimulating tumor cells and spleen cell factor(s).

Abstract

The ability of 3 cultured mouse tumor lines to stimulate a cytotoxic response in 5-day cultures of allogeneic lymph node cells was studied with a 51Cr release assay. Two lines of mesenchymal origin, P815 [mastocytoma] and EL-4 [lymphoma], were highly stimulatory, whereas the third cell line, CaD2, a mammary gland epithelial tumor, did not stimulate over a wide range of cell concentration. CaD2 cells contained major antigens similar to those of P815 cells as shown by the specific lysis of both cells by lymphocytes activated to H-2d-bearing peritoneal cells. UV-irradiated P815-cells, like .gamma.-irradiated CaD2 cells, did not stimulate a cytotoxic response, but both cell lines stimulated a full and specific response to allogeneic lymph node cells if these mixed cultures were supplemented with a supernatant harvested from concanavalin A-stimulated spleen cells.