The DA6-147 monoclonal antibody raised against the HLA-DR alpha chain identifies a cryptic epitope on the BoLA-DR alpha chain.

By combining immunoprecipitation of BoLA molecules with monoclonal antibodies raised against 2 different major histocompatibility class II antigens, TH14B and TH81A, and western blotting using the anti-HLA DR alpha monoclonal antibody DA6-147, we characterized an epitope conserved on BoLA- and HLA-DR alpha chains. This epitope, not accessible on intact cells, was revealed after cell lysis. In addition, these results allowed us to define TH14B as an anti-BoLA-DR monoclonal antibody whereas TH81A, raised against the products of a second MHC locus, is probably an anti-BoLA-DQ monoclonal antibody.