Properties of Monoclonal Antibodies Specific for Determinants of a Protein Antigen, Myoglobin

Monoclonal hybridoma antibodies specific for the protein antigen sperm whale myoglobin were produced using hyperimmune spleen cells from mice with the genetic trait of high responsiveness to myoglobin. Antibodies from the several clones tested were found to produce linear Scatchard plots, as predicted for homogeneous antibodies, and to possess high affinities for the immunogen (KA congruent to 10(9) M-1). None of the monoclonal antibodies tested reacted with either fragment (1-55) or fragment (132-153) of sperm whale myoglobin. Competitive binding assays using human and horse myoglobins suggested that several of these monoclonal antibodies, which can readily distinguish these myoglobins, recognize different antigenic determinants on the myoglobin molecule. Studies using additional myoglobin sequence variants as competitors should be able to more closely define these antigenic determinants.