Human natural anti-alpha-galactosyl IgG. II. The specific recognition of alpha (1----3)-linked galactose residues.
A natural IgG antibody (anti-Gal) with alpha-galactosyl binding specificity has been found in large amounts (0.5 - 1.0% of serum IgG) in all individuals tested. It has been purified by affinity chromatography on a column of melibiose-Sepharose. In addition to its affinity for normal and pathological senescent human red cells, the antibody readily interacts with rabbit red blood cell (RRBC) glycolipids with alpha-galactosyl terminal residues. Two types (glycosidic linkages of 1----3 vs. 1----4) of rabbit red cells glycolipids with terminal alpha-galactosyl residues were tested for antibody binding. The antibody specifically bound to glycolipids with Gal alpha 1----3 terminal residues, and treatment of these glycolipids with alpha-galactosidase abolished binding. Hemagglutination inhibition studies with oligosaccharides of known structure also showed that the antibody binds specifically to glycoconjugates with an alpha 1----3 terminal galactose residue. Anti-Gal did not bind to a human B-active glycolipid, indicating that fucose-linked alpha 1----2 to the penultimate galactose prevents anti-Gal binding. The anti-Gal specificity for RRBC glycolipids also paralleled that of the alpha-galactosyl-specific Bandeiraea simplicifolia lectin. The possible reasons for the occurrence of this unique antibody in human serum are discussed.
Galili
U
U
Macher
B A
BA
Buehler
J
J
Shohet
S B
SB
D000017:ABO Blood-Group System / Q000276:immunology; D000818:Animals; D000918:Antibody Specificity; D002236:Carbohydrate Conformation; D000939:Epitopes / Q000276:immunology; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000276:immunology; D004913:Erythrocytes, Abnormal / Q000276:immunology; D005690:Galactose / Q000276:immunology*; D005732:Gangliosides / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D007074:Immunoglobulin G / Q000276:immunology*; D037102:Lectins / Q000276:immunology; D037121:Plant Lectins; D011817:Rabbits
D000017:ABO Blood-Group System; D000939:Epitopes; D005732:Gangliosides; C045475:Griffonia simplicifolia lectins; D007074:Immunoglobulin G; D037102:Lectins; D037121:Plant Lectins; D005690:Galactose