EVIDENCE FOR THE EXPRESSION OF 3 DIFFERENT BOLA-CLASS-II MOLECULES ONTHE BOVINE BL-3 CELL-LINE - DETERMINATION OF A NON-DR NON-DQ GENE-PRODUCT

Studies were conducted to determine the reactivity of six monoclonal a ntibodies specific for major histocompatibility complex class II molec ules expressed on a bovine B cell line homozygous for BoLA-DR and BoLA -DQ alleles. Direct immunoprecipitation, serial immunodepletion experi ments, and two-dimensional gel electrophoresis revealed that these ant ibodies reacted with three different molecules. Bovine orthologues of HLA-DR were recognized by three monoclonal antibodies - H34A, TH12A, a nd TH14B. Orthologues of HLA-DQ were characterized by two other monocl onal antibodies, TH22A and TH81A. A third BoLA class II antigen, neith er DR nor Da was revealed by the last monoclonal antibody H42A. The re lation of this molecule to known molecules in humans and other species remains to be established. However, cumulative data suggest that the determinant is expressed on a molecule related to HLA-DP.