Recognizes a sialoglycoprotein of 39kDa, identified as glycophorin A (GPA). It is present on red blood cells (RBC) and erythroid precursor cells. It has been shown that glycophorin acts as the receptor for Sandei virus and parvovirus. Glycophorins A (GPA) and B (GPB), which are single, trans-membrane sialoglycoproteins. GPA is the carrier of blood group M and N specificities, while GPB accounts for S and U specificities. GPA and GPB provide the cells with a large mucin like surface and it has been suggested this provides a barrier to cell fusion, so minimizing aggregation between red blood cells in the circulation.