Evaluation of Salmonella antisera for an optimum enzyme-linked antibody detection of Salmonella using hydrophobic grid membrane filters

Abstract

A library of 566 serovars of Salmonella representing 11 serogroups, arizonae strains, rough and untypable strains in arrays on hydrophobic grid membrane filters (HGMFs) was replicated and the replicates treated using various chemical agents to expose the antigenic components that reacted best with 46 monoclonal and polyclonal antibodies to Salmonella . For polyclonal antibodies no pretreatment was necessary, but boiling HGMFs for 10 s at either pH 1 or 13 was essential to expose the appropriate epitopes for the monoclonal antibodies. After staining the pretreated HGMFs with an enzyme-linked antibody (ELA) procedure, two antibodies showed great promise for detecting strains within the genus Salmonella . Monoclonal antibody S. typhi 4 2 identified all but one of the 566 salmonellae and none of the 282 other Gram-negative organisms tested. Another monoclonal antibody, M105, had a reaction pattern identical to that of S. typhi 4 2 except that it also reacted with two of 16 Enterobacter strains. S. ealing , belonging to serogroup O, was the serovar missed by both monoclonal antibodies; S. alachua , the other serovar tested in this group, was detected. To eliminate the possibility that some of group O Salmonella could be missed, a combination of S. typhi 4 2 or M105 with other antibodies (monoclonal 3B9 or Spicer Edwards) that reacted with both group O strains could be used. Our study identified the antibody having the fewest false-positive and negative results in an ELA procedure for detection of Salmonella . In addition, it was discovered that five of the monoclonal antibodies were specific for group D Salmonella .