Characterization of a monoclonal antibody against a 24KD antigen from rat testis important for fertility regulation

Abstract

Monoclonal antibodies were raised against a 24KD antigen from rat testicular cytosol which was previously shown to produce antibody titres in rats with inhibitory effect on fertility. Of the 20 hybridoma clones selected for study, one clone HS-D5 was finally chosen for characterisation as it proved to be functionally promising. The clone was secreting IgM type of antibody. it produced strong agglutination of human sperm and prevented binding of hamster sperm to hamster oocyte. In localization studies it identified the acrosome of sperm of multiple species. Western blots with rat testicular cytosol and human sperm extracts showed a strong band at around 24KD with HS-D5. On Western blots from two dimensional gels, HS-D5 identified multiple spots at the region of 24KD. The mechanism of action of the antibody seemed to be at the level of interaction of the oocyte and spermatozoa.