Partial purification and characterization of chicken immune-associated antigen in serum coded for by the major histocompatibility complex.

Chicken serum contains 3 molecular species of immune-associated (Ia) antigen coded for by the major histocompatibility complex (MHC). These molecules are named B-L alloantigens [1]. They vary in electrophoretic migration velocity and molecular size [2]. The aim of this study was to characterize one of the antigen species - the low molecular size form. Therefore, we performed a partial purification by: (i) affinity chromatography; and (ii) ammonium sulfate precipitation of serum B-L antigen from the chicken plasma. Since the MHC-antigens were known to be glycoproteins, the purification was based on lectin affinity chromatography, as previously used for the membrane-bound MHC-antigens [3]. Electro-immunochemical analysis using rabbit antibodies against the chicken lymphocyte plasma membrane and the partially purified antigen were employed to monitor the purification and to characterize the different molecular forms of the Ia molecules. The partially purified preparation was then analyzed to elucidate the biochemical structure of the serum B-L antigen. Finally, rabbit antiserum was raised against this preparation to evaluate its level of purity and to follow further purification of this molecule.