Chemical and immunological characterization of developmentally expressed chicken erythroid surface membrane antigens

The expression of two hematopoietic-lymphoid membrane antigens, referred to as chicken fetal antigen (CFA) and chicken adult antigen (CAA) were investigated on primitive and definitive peripheral red blood cells (RBC) from different-aged chickens using chemical and immunological techniques. Differential adsorptions of antisera specific for adult RBC membrane antigens permitted the serological dissection of CAA into eight antigenic determinants. CFA and CAA were assayed by hemagglutination, hemolysis, and immune precipitation of radioiodinated surface antigens of RBC from different-aged chickens. Primitive RBC express CFA, while definitive RBC express three distinct phenotypes: CFA, both CFA and CAA, or CAA, depending on the developmental age of the chicken from which the RBC were obtained. When solubilized membrane extracts of radioiodinated peripheral RBC from chickens at 5 and 18 days embryonic development (E5 and E18, respectively), 13 days posthatch development (H13), and adult chickens were immunoprecipitated and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the major antigen detected by anti-CFA sera was associated with proteins having apparent molecular weights (M_r) of 50,000 daltons (50 kd). The antigens detected by anti-CAA sera were associated with proteins having apparent M_r of 102, 81, 48, and 43 kd.