INDUCTION OF MACROPHAGE-MEDIATED TUMOR LYSIS BY THE LECTIN WHEAT-GERM-AGGLUTININ

  • 1 January 1980
    • journal article
    • research article
    • Vol. 40  (10) , 3798-3803
Abstract
The 1st step in macrophage-mediated tumor lysis, effector-target contact, was studied in a C3H/He mouse-MM46 syngeneic tumor system in which antibody-dependent tumor lysis by macrophages (ADMC) was observed in vitro. Various lectins were tested for the ability to mediate the contact between effector macrophages and target tumor cells. Wheat germ agglutinin (WGA), Con A, phytohemagglutinin and pokeweed mitogen induced this contact, but only WGA also induced tumor lysis by macrophages. This lectin-dependent cytolysis by macrophages (LDMC) and the cytoadherence between macrophages and tumor cells induced by WGA were inhibited by N-acetylglucosamine, a sugar specifically recognized by WGA. In the LDMC reaction, macrophages in the presence of WGA could kill other syngeneic and allogeneic tumor cells but not normal thymus or spleen cells. WGA is a ligand in macrophage-mediated cytolysis, inducing the binding of effector cells to target cells that triggers off lysis of the target cells. ADMC, but not LDMC, was inhibited by aggregated immunoglobulin and by protease pretreatment of macrophages. The mechanisms of recognition in LDMC and ADMC are different, but both ligands can induce the lytic reaction.