[Examination of antigen preparations from the virus of enzootic bovine leukosis with regard to suitability for immunoblotting].

8 different leukosis antigen preparations for immunodiffusion from 6 European countries were examined regarding their suitability for immunoblotting. Emphasis was made on demonstration of immunoreactions at 51 kDa beside reactions at 24 kDa. The whole protein content of the different preparations varied very much. gp 51 could be detected only by monoclonal antibodies at a molecular weight of 53 kDa, in one preparation at 26 kDa. With sera from field or with the European reference serum E4 none or only weak reactions could be observed at these molecular weights. All antigen preparations contained bovine IgG that is divided in L- and H-chains by SDS-electrophoresis under reducing conditions. These single chains reacted also with anti-bovine-IgG-biotin conjugate und disturbed the detection of the leukosis specific reactions. The bovine IgG could be removed by a Protein-G-column. One of all tested leukosis antigens, which are prepared for immunodiffusion, was suitable for immunoblotting. This antigen preparation contained only few bovine IgG and had strong reactions at 24 kDa. A special antigen preparation for detection of other reliable immunoreactions in the immunoblot has to be developed.