A monoclonal antibody against bovine anti-Müllerian hormone.

Anti-Müllerian hormone (AMH) was partially purified from incubation medium of calf fetal testes and injected into a BALB/c mouse, whose splenocytes were fused with Sp2/Ag8 myeloma cells. Hybridomas were screened for specific antibody production by double antibody precipitation of labeled AMH, which was obtained by incubating fetal calf testes in the presence of tritiated fucose and submitting the medium to the standard procedure of purification. In spite of the extremely low concentration of AMH in the preparation used for immunization, three hybridomas gave positive results in the screening assay. One was cloned and grown in mice. The monoclonal antibody purified from ascites fluid abolished anti-Müllerian activity of partially purified AMH, whether or not the immune complex was removed from solution by a second, antimouse immunoglobulin antibody. The monoclonal antibody also blocked anti-Müllerian activity of calf but not rat fetal testes. Our results indicate that the monoclonal antibody is species specific and is directed towards the antigenic determinant responsible for biological activity.