CHARACTERIZATION AND MITOGENICITY OF A LECTIN FROM ERYTHRINA-VELUTINASEEDS

A purified lectin from Erythrina velutina was found to be a dimeric gl ycoprotein of M(r) ca 62 000 with a neutral sugar content of 5.8%. It agglutinated human A, B and O erythrocytes and rabbit red cells at min imal concentrations of 1.95 and 2.30 mu g ml(-1), respectively. In con trast, horse or cow erythrocytes were agglutinated only after neuramin idase or trypsin treatment. The haemagglutinating activity of the lect in was inhibited by D-galactose and related saccharides. N-Acetyllacto samine, the most potent inhibitor, was 95 times more effective than ei ther lactose or galactose. N-Acetylgalactosamine was about four times as active as lactose. Asialomucin from porcine stomach, a glycoprotein rich in N-acetyllactosamine-containing O-glycans, also acted as an in hibitor. Mitogenic activity on normal human lymphocytes was obtained a t an optimal concentration of ca 125 mu g ml(-1). Mononuclear cells fr om patients with Localized American Cutaneous Leishmaniasis proliferat ed in the presence of the lectin; the stimulation index was similar to that obtained with cells from healthy individuals.