IDENTIFICATION OF MYCOPLASMA-SYNOVIAE IMMUNOGENIC SURFACE-PROTEINS AND THEIR POTENTIAL USE AS ANTIGENS IN THE ENZYME-LINKED-IMMUNOSORBENT-ASSAY

Specific immunogenic proteins of Mycoplasma synoviae (MS) strain WVU-1 853 were purified and characterized by sodium dodecyl sulfate-polyacry lamide gel electrophoresis and by Western transfer using anti-MS, anti -M. gallisepticum, and non-immune chicken sera. A cluster of prominent immunoreactive proteins with molecular masses from 46 to 52 kDa (p46- 52) and less reactive single proteins of approximately 22 and 92 kDa w ere shown to partition into the detergent phase of Triton X-114 MS lys ates, suggesting that these amphiphilic polypeptides are integral memb rane proteins. Monoclonal antibodies, produced by immunizing mice with MS whole cell proteins and shown to bind species-specific determinant s, reacted strongly with p46-52 and less intensely with the 22-kDa pro tein, but they did not react with the 99-kDa protein. A protein fracti on extracted from the Triton X-114 detergent phase and further purifie d by ion-exchange chromatography was found to be highly enriched in p4 6-52 and was used as antigen in a prototype enzyme-linked immunosorben t assay (ELISA) to detect MS antibodies. Seventy serum samples were ta ken variously from specific-pathogen-free chickens experimentally infe cted with MS or MG and from commercial broiler breeder chickens vaccin ated for MS and MG. All samples were tested by both rapid serum agglut ination and a prototype ELISA described herein; the two tests were str ongly correlated (r = 0.776). The results indicate that the ELISA anti gen used-the immunodominant cell surface proteins in the p46-52 cluste r-appears to be a good candidate for use in the development of improve d rapid diagnostics of MS infections in birds.