The role of lymphocyte surface binding sites for wheat germ agglutinin in the negative regulation of cancer patients.

The role of lymphocyte surface binding sites for wheat germ agglutinin (WGA) in the negative regulation of cancer patients was investigated. The number of WGA binding sites on the surface of each lymphocyte ranged from 10(7) to 10(8). Fluorescein isothiocyanate (FITC)-conjugated WGA, bound to the majority of peripheral blood lymphocytes (PBL) with two peaks of fluorescent intensity was expressed either dimly or brightly. The increase in lymphocytes brightly expressing WGA fluorescent intensity (WGA bright lymphocytes) significantly correlated with the number of WGA binding sites. The suppression of lymphocyte proliferation mediated by the purified soluble suppressor factor (SSF) significantly correlated with an increase in the WGA bright lymphocyte population (P < 0.05). A significantly greater number of WGA bright lymphocytes in PBL was found in patients with esophageal, gastric, breast, or colon cancer, than in those with benign diseases or in healthy controls. Furthermore, an increase in WGA bright lymphocytes was found in subsets expressing the antigens CD8 dimly or CD16. Thus, it is suggested that the number of WGA binding sites may increase mainly on the surface of effector cells such as NK cells and CD8-positive killer T cells in cancer patients, triggering the negative regulation mediated by SSF.