LYMPHOCYTE CELL-SURFACE GLYCOPROTEINS WHICH BIND TO SOYBEAN AND PEANUT LECTINS

Abstract

In cellular immunology, peanut (A. hypogaea) lectin is used to selectively agglutinate immature lymphoid cells and soybean (G. max) lectin to agglutinate B lymphocytes. Affinity chromatography was used to study the surface glycoproteins of rat and mouse lymphoid cells which bind to these lectins. Thymocyte and T and B lymphocyte glycoproteins were analyzed either without modification (native) or after the removal of sialic acid with neuraminidase (asialo). The only native glycoprotein which bound to peanut lectin was the 95,000 MW sialoglycoprotein from thymocytes. The equivalent molecule from T lymphocytes bound to peanut lectin only after neuraminidase digestion. The selective agglutination of thymocytes by peanut lectin would seem to be due to a partial lack of sialic acid residues on the O-glycosidically-linked oligosaccharides of the thymocyte sialoglycoprotein. The B lymphocyte form of the leukocyte-common antigen was the only prominent native glycoprotein which bound to soybean lectin and this probably accounts for the specific binding of this lectin to B cells. The leukocyte-common antigens, in their asialo forms, from thymocytes and B and T lymphocytes differed in their binding to the lectins and this establishes that these glycoproteins which share antigenic determinants differ in their carbohydrate structures.