Monoclonal antibodies to Mycoplasma gallisepticum membrane proteins.

Monoclonal antibodies (MAbs) were prepared to study the immunogenesis of Mycoplasma gallisepticum. Balb/c mice were immunized with M. gallisepticum immunostimulating complexes and the supernatant of heterokaryotes screened with M. gallisepticum and closely related M. synoviae as antigens in indirect enzyme-linked immunosorbent assay. All selected MAbs proved to be M. gallisepticum species-specific when they were tested against 10 different avian Mycoplasma species. After immunoblotting analysis, five polypeptides were identified with estimated molecular weights of 110,000, 66,000, 64,000, 56,000, and 50,000. Cell membrane localization of the recognized polypeptides was studied by immunoelectron microscopy. None of the MAbs inhibited the hemagglutinating activity of freshly prepared M. gallisepticum. However, one MAb (B3) specific for p56 agglutinated the stained M. gallisepticum antigen in the slide agglutination test. Results seemed to correlate with published information on the protein composition and agglutinating activity of Mycoplasma gallisepticum.