A RED-CELL BAND 3 VARIANT WITH ALTERED STILBENE DISULFONATE BINDING IS ASSOCIATED WITH THE DIEGO (DIA) BLOOD-GROUP ANTIGEN

1. We have shown that the Di(a) antigen of the Diego blood group system is associated with the presence of red cell band 3 Memphis, but not all band 3 Memphis samples carry the Di(a) antigen. 2. The band 3 Memphis associated with the Di(a) antigen was covalently labelled by 4,4'-di-isothiocyanato-1,2-diphenylethane-2,2'-disulphonic acid (H2DIDS) more readily than was normal band 3 or band 3 Memphis not associated with the Di(a) antigen. This altered reactivity with H2DIDS has previously been noted for a band 3 Memphis sub-type designated variant 2. 3. This is the first example of a band 3 polymorphism associated with an antigenic change in the extracellular region of the band 3 polypeptide and with altered H2DIDS binding.