Limulin (Limulus polyphemus lectin): mitogenic effect on human peripheral lymphocytes.

The lectin from hemolymph of Limulus polyphemus was purified by affinity chromatography on insolubilized bovine submaxillary mucin. The purity of the protein was checked by crossed immunoelectrophoresis. Agglutination of human red blood cells was completely abolished after neuraminidase treatment, while other cells were still agglutinable after the same treatment but required a higher concentration of lectin. Limulin was able to simulate about 50% of human peripheral lymphocytes. This mitogenic effect could be inhibited by bovine submaxillary mucin but not by the disialylated mucin. Related to the known oligosaccharide-binding specificity of limulin and of the other nonspecific activators of lymphocytes, the authors suggest that lymphocyte stimulation is triggered by binding to a glyco-conjugate bearing the following carbohydrate chains: NANA leads to GalNac leads to or NANA leads to Gal leads to GlcNAc leads to Man.