One-step purification of murine IgM and human [alpha]2-macroglobulin by affinity chromatography on immobilized snowdrop bulb lectin

Abstract

A new mannose-specific plant lectin (GNA) isolated from the snowdrop bulb was immobilized on Sepharose 4B and employed for the purification of certain glycoproteins with high-mannose type glycan chains. Murine IgM bound tightly to this column and was eluted with 0.1 methyl [alpha]--mannoside whereas bovine and murine IgG were not bound. When a murine hybridoma serum containing IgM monoclonal antibody was applied to this column, highly purified IgM antibody was obtained after elution with methyl [alpha]--mannoside. On the contrary, human IgM was not bound by this column despite reports that it contains high-mannose type glycan chains. [alpha]2-Macroglobulin was the sole glycoprotein present in human serum which was bound by the immobilized snowdrop lectin column. It appears that only glycoproteins containing multiple Man-([alpha]1,3)Man units are bound to the immobilized lectin.