Identification of target proteins participating in a lectin-dependent macrophage-mediated cytotoxic reaction.

Membrane proteins of mouse macrophages and mammary tumor cells having affinity to Sarcophaga lectin were isolated by affinity chromatography. The electrophoretic profiles and antigenicities of lectin-binding proteins from macrophages and tumor cells were different. Antibody raised against tumor cell lectin-binding proteins inhibited both the binding of the lectin to tumor cells and the lectin-dependent macrophage-mediated cytotoxic reaction. However, it did not inhibit the binding of the lectin to macrophages. It was suggested that the same lectin molecule transmitted different stimuli to macrophages and tumor cells via different receptor proteins.