Cell-mediated cytotoxic activity of spleen cells from patients with gastric carcinoma.

The cell-mediated cytotoxic activities of cells from the spleens (SP cells) of patients with gastric carcinoma were assayed in comparison with the activities of peripheral blood mononuclear cells (PBM cells) from the same patients, and from patients with benign lesions. The natural killer cell (NK) activity of the SP cells and their capacity to generate allogeneic cytotoxicity in mixed lymphocyte culture (MLC) were very similar to those of the PBM cells. The cytotoxic activity of SP cells induced by alloactivation in MLC, however, was significantly higher than that of the PBM cells from the same patient as well as from patients with benign lesions. The production of interleukin 2 (IL 2) and the ability to induce cytotoxic cells after activation with IL 2 (LAK) were therefore examined. Both the ability to produce IL 2 and to generate LAK cells were shown to be significantly increased in SP cells when compared to PBM cells. These results indicate that the spleen may be a potential reservoir for the precursors of these activated killer cells in patients with gastric carcinoma. Furthermore, it may play an important role in the defence against tumors in these patients.