CHARACTERIZATION OF MONOCLONAL-ANTIBODIES AGAINST A FIMBRIAL STRUCTURE OF SALMONELLA-ENTERITIDIS AND CERTAIN OTHER SEROGROUP-D SALMONELLAE AND THEIR APPLICATION AS SEROTYPING REAGENTS

A panel of 13 monoclonal antibodies from different hybridomas was prod uced against a novel salmonella fimbrial antigen expressed predominant ly by Salmonella enteritidis strains. The specificity of the monoclona l antibodies to this antigen (SEF14) was confirmed by enzyme-linked im munosorbent assay (ELISA) using purified SEF14, immune electron micros copy and, with 11 monoclonal antibodies, the identification of a repea ting protein subunit (14,300kDa) on the antigen. Blocking-ELISA with t he monoclonal antibodies identified epitopes in at least three, non-ov erlapping clusters which appeared evenly distributed on SEF14 in immun e electron microscopy. The use of the monoclonal antibodies in direct- binding ELISA on a range of salmonella serotypes suggested that the ep itopes on SEF14 are highly conserved and were expressed by all the S e nteritidis strains examined; some strains of S dublin and the only str ain of S moscow available were the only other serotypes that expressed SEF14. A latex agglutination reagent based on a monoclonal antibody w as developed and used to test for SEF14 on 280 strains (representing 1 20 serotypes in 24 serogroups of salmonellae) that had been grown on S ensitest agar for 18 hours at 37-degrees-C. All S enteritidis strains (64) and most S dublin strains (28 of 33) produced SEF14 as did the tw o strains representing S blegdam and S moscow. SEF14 was not detected in any other strains of serotypes from serogroup D or from any other s erogroup examined.