Epitope Mapping of Monoclonal Antibodies to gag Protein p19 of Avian Sarcoma and Leukaemia Viruses

We have characterized a set of 15 monoclonal antibodies to p19gag, one of the internal proteins of avian sarcoma and leukaemia viruses. All the antibodies work in immune precipitations as well as in immunoblotting, though with different efficiencies. We have developed a simple epitope mapping technique, which uses partial chemical cleavages at methionine or tryptophan residues followed by immunoblotting from SDS-polyacrylamide gels, to localize the epitopes of nine of these antibodies. The epitopes fall into at least four classes. The mapping procedure should also be useful for other antigens of known primary structure.