Generation of senescent antigen on erythrocytes by partial blocking of SH groups of the membrane proteins.

Human erythrocytes treated with diamide (0.2 mM) or N-ethylmaleimide (0.1 mM) at 37 degrees C for 1 h were susceptible to binding of anti-band 3 immunoglobulin G autoantibody and hemoglobin. A definite degree of cell modification appeared to be required for the effective bindings since the cells treated with the reagents above these concentrations were less susceptible. The enhanced binding activities of the cells treated with diamide were abolished on treatment with dithiothreitol. Partial blocking of SH groups of the membrane proteins but not disulfide-mediated protein cross-linking may be essential for the formation of band 3 senescent antigen, which may not be a neo-antigen formed by chemical modification of band 3 but an antigen formed by topological alterations of the molecules in the membrane.