Terminal galactose residues and the antigenicity of Plasmodium falciparum glycoproteins

The presence of terminal α- d-galactosyl residues in the carbohydrate chains of glycoprotein antigens from the asexual blood stages of Plasmodium falciparum is demonstrated by (1) the α- d-galactosidase sensitivity of particular parasite antigens, (2) the use of specific glycosidases to cleave sugars from parasite glycoproteins radiolabeled with [ 3H]glucosamine, and (3) the ability of Bandeirea simplicifolia lectin, which has a specificity for terminal α-galactosyl residues, to bind to the parasite. The carbohydrate side chains, and in particular the terminal α-galactosyl residues, are shown to have an important role in determining the binding of antibodies to parasite glycoproteins.