The mouse monoclonal antibody HIR2 recognizes an epitope within the N-terminal (extracellular) portion of CD235a (glycophorin A) and CD235b (glycophorin B). Its antigen is expressed on early erythroblasts, late erythroblasts, erythroblasts, mature erythrocytes and the cells of erythroid cell lines K562 and HEL, but not on all other cells.
CD235a (glycophorin A, GPA) is a transmembrane sialoglycoprotein expressed on erythrocytes and their precursors. Similarly to CD235b (glycophorin B, GPB), these molecules provide the cells with a large mucin-like surface, which minimalizes aggregation between erythrocytes in the circulation. GPA is the carrier of blood group M and N specificities, while GPB accounts for S, s and U specificities. CD235a is a receptor of Hsa, a Streptococcus adhesin.,Glycophorin A/B, GYPA/B, GPA/B, PAS-2/3, Sialoglycoprotein alpha/beta, GPSAT, GPErik, MSN blood group