FURTHER CHARACTERIZATION OF A MONOCLONAL-ANTIBODY REACTIVE WITH ESCHERICHIA-COLI O157-H7

Monoclonal antibody (MAb) 4E8C12 has been previously reported to recog nise low mel. wt proteins from enterohaemorrhagic Escherichia coli (EH EC) serotypes O157:H7 and O26:H11. Crude lipopolysaccharide (LPS) prep arations from proteinase K-digested bacterial suspensions reacted in W estern blots with MAb 4E8C12, as did highly purified LPS from O157:H7 strains. The material recognised by this antibody was, therefore, LPS. The LPS epitope was identified by a whole-cell ELISA in several EHEC, verotoxin producing E. coli (VTEC) and verotoxin-negative strains in addition to E. coli serotypes O157:H7 and O26:H11. Acriflavine and bil e salts enhanced the production or availability of the epitope at the cell surface and in culture supernates. These data indicate that the p resence of the epitope did not correlate with the virulence of these o rganisms.