D-galactose-specific lectin, binds the T-antigen structure Gal-beta1,3-GalNAc (Thomsen-Friedenreich-antigen-specific lectin). Potent and selective stimulant of distinct T- and B-cell functions. Shows a unique ability to specifically recognize IgA-1 from human serum (By similarity). Tetramer of four alpha chains associated with two or four beta chains. Belongs to the jacalin lectin family.