The Wrb antigen, a receptor for Plasmodium falciparum malaria, is located on a helical region of the major membrane sialoglycoprotein of human red blood cells.

1. Immunoprecipitation of periodate/NaB3H4-labelled human erythrocytes using anti-Wrightb (Wrb) monoclonal antibodies showed that these antibodies specifically react with the major erythrocyte sialoglycoprotein alpha (glycophorin A). 2. Similar experiments on erythrocytes from the only known individual lacking the Wrb antigen but with otherwise normal sialoglycoproteins did not result in the immunoprecipitation of any sialoglycoprotein. 3. We suggest that the Wrb antigen is located on an alpha-helical region between residues 55 and 70 of sialoglycoprotein alpha.