Comparison of allogeneic and xenogeneic determinants on the H-2Kk molecule

Two monoclonal rat anti-H-2 antibodies were derived by cell fusion from a rat immunized with mouse CH-1 lymphoma cells. Both antibodies recognize polymorphic H-2 determinants expressed on most haplotypes. Competitive binding studies on H-2Kk show that one rat antibody, R1-9.6, detects a determinant that is distant from the allodeterminants defined by 12 different mouse monoclonal anti H-2 antibodies. In contrast, the rat antibody R1-21.2 inhibits the binding of most mouse monoclonal anti H-2 antibodies to H-2k cells, possibly by causing a conformational change in the H-2 molecule. Both antibodies bind strongly to H-2 molecules and can be used for structural and biochemical studies.