Cell-mediated cytotoxicity of mononuclear cells isolated from cancer and normal mucosa of the stomach.

Mononuclear cells from the organized gut-associated lymphoid tissues of gastric cancer patients or cancer-free individuals were examined for the number of K cells in antibody-dependent cellular cytotoxicity and target cell reduction in microcytotoxicity assays. Mononuclear cells were isolated from cancer tissue, gastric mucosa, intestinal mucosa, peripheral blood, spleens, tonsils, thymus, and the mesenteric lymph nodes of gastric cancer patients or the non-gastric cancer group. K cells against sheep erythrocytes were found in peripheral blood mononuclear cells of both gastric cancer patients and cancer-free individuals, and to a lesser extent in mucosal mononuclear cells from gastric cancerous and noncancerous areas and spleens of both groups. No significant differences in the number of K cells were observed between mononuclear cells from gastric cancerous areas and noncancerous areas. On the other hand, microcytotoxicity assay effector cell activities against allogeneic gastric cancer cell lines were significantly higher in mucosal mononuclear cells from gastric cancerous areas than those from noncancerous areas. Peripheral blood mononuclear cells of gastric cancer patients showed relatively low microcytotoxicity assay activity at an effector to target cell ratio of 10:1, but not 30:1 as compared with that in mucosal mononuclear cells from gastric cancerous areas, spleens, and peripheral blood mononuclear cells of the non-gastric cancer group. Cells from lymph nodes, tonsils, and thymus did not have K cells and showed low microcytotoxicity assay activities. These results demonstrate that mucosal mononuclear cells from gastric cancerous areas may possibly show different behavior from those from noncancerous areas with regard to cell-mediated cytotoxicity.