IDENTIFICATION OF CHICKEN BU-1 ALLOANTIGENS USING THE MONOCLONAL-ANTIBODY AV20

The genetically polymorphic chicken antigen Bu-1 (chB6) has been ident ified by alloantisera raised against RPL line 6(3) (Bu-1a) and line 7( 2) (Bu-1b) birds and subsequently by monoclonal antibodies (mAbs) whic h identify individual alloantigens. We have produced a monoclonal anti body, AV20, which recognises a monomorphic determinant on the antigen Bu-1. AV20 identifies a marker on both bursal and peripheral B cells. Staining characteristics on bursa, spleen, thymus and peripheral blood lymphocytes are similar to those of the allotypic antibodies which id entify Bu-1a and Bu-1b. However, AV20 identified B cells in partially inbred birds as well as inbred lines including line 6(1) and line 7(2) , indicating that it recognises a monomorphic determinant. AV20 immuno precipitated an antigen with a Mw(r) of 150 kDa under non-reducing con ditions and 70-75 kDa under reducing conditions indicating it is a hom odimer. Serial immunoprecipitations of bursal-cell lysates from line 6 (1) or line 7(2) confirmed that AV20 recognised the same antigen as mA bs against Bu-1a and Bu-1b in the respective lines.