CD235a recognises a 39 kd sialoglycoprotein identified as glycophorin A. It is abundantly expressed on red blood cells and erythroid presursor cells. It has been shown that glycophorin acts on the erythrocyte binding antigen (EBA-175) of P. falciparum as well as the receptor for Sandei virus, parvovirus, influenza virus and hepatitis A virus. Two types of glylocophorins are indentified and classified as glycophorin A (GPA) and glycophorin B (GPB). Both are trans-membrane sialoglycoproteins. GPA is the career of M and N antigens specific blood group whereas GPB is for the S and U specificities.