Detection of Escherichia coli cytotoxins by enzyme-linked immunosorbent assays

Sandwich enzyme-linked immunosorbent assays (ELISAs) were developed to detect Escherichia coli cytotoxins. Wells were coated with monoclonal antibodies from hybridomas 13C4 and (or) 11E10, and biotin conjugates of these antibodies were used for detecting verotoxin 1 and Shiga-like toxin II, respectively. Sensitivities were about 100 and 200 cytotoxic doses, respectively. Verotoxin 2 was detected by ELISA with monoclonal antibody 11E10, but at a sensitivity of only about 4000 cytotoxic doses. ELISA results of polymyxin-treated cell extracts from cultures of 67 E. coli strains were in agreement with Vero cell assay as regards the presence and type of toxin.