Biochemical polymorphism of B-G and B-F antigens of the chicken major histocompatibility complex.

To refine and improve the definition of the polymorphism of the chicken B-complex at the level of expressed products we used a biochemical approach, including SDS-PAGE and/or IEF. In chickens this approach appeared as successful as in several other species. Chickens of a commercial pure White Leghorn line were typed for B-F (class I) and B-G (class IV) major histocompatibility (B) complex antigens by two methods. Serotyping was performed by direct haemagglutination using alloantisera raised against erythrocytes. Biochemical analysis involved immunoprecipitations from radiolabelled cells using monoclonal antibodies recognizing monomorphic determinants of B-F (F21-2) or B-G (18-6G2) followed by analysis on SDS-PAGE and/or IEF. Specific banding patterns of B-G proteins were observed by 1D-IEF. Moreover, separation on molecular weight of B-G proteins also enabled a precise identification of these B-G types. Within the White Leghorn line there were no discrepancies between serotypes and typing patterns for B-G by either IEF or SDS-PAGE. Analysis of B-F immunoprecipitates enabled us to identify B-F polymorphism separately of B-G. Identical B-F patterns were found with two different B-G types, indicating that in these chickens recombinations between B-F and B-G have occurred.