Griffonia simplicifolia I lectin mediates macrophage-induced cytotoxicity against Ehrlich ascites tumor.

The concurrent administration of Griffonia simplicifolia lectin into the peritoneal cavity of mice has been reported to protect them from challenge with Ehrlich ascites tumor cells. This study demonstrates that the GS I lectin is capable of binding to the surface of both inflammatory macrophages and Ehrlich ascites tumor cells and can mediate macrophage lectin-dependent cytotoxicity to this tumor cell line. The lectin was not found to be toxic to Ehrlich ascites tumor cells directly or to nonspecifically initiate complement-mediated lysis of these target cells. The macrophage lectin-dependent cytotoxicity could be specifically inhibited by the haptenic sugar methyl a-D-galactopyranoside. Thus, this lectin appears to be able to provide a linkage between effector macrophages and Ehrlich ascites tumor cells resulting in the triggering of a cytolytic event.