Concanavalin A induces formation of osteoclast-like cells in RAW 264.7 mouse macrophage cells

The effect of lectins on the formation of osteoclasts in RAW 264.7 mouse macrophage cells was examined. Concanavalin A (Con A) induced the formation of multinucleated giant cells (MGC) whereas pokeweed mitogen and phytohemagglutinin did not do it. Con A-induced MGC were positive for tartrate-resistant acid phosphatase (TRAP) activity, a histochemical marker of osteoclasts. Murine splenic macrophages differentiated into TRAP-positive and multinucleated cells in response to Con A whereas peritoneal macrophages did not. The culture supernatant from Con A-stimulated RAW 264.7 cells did not cause the MGC formation. The relationship between Con A-induced GMC formation and osteoclastgenesis is discussed.