EPITOPE SPECIFICITY OF A MONOCLONAL-ANTIBODY GENERATED AGAINST THE DISSOCIATED CFA I FIMBRIAE OF ENTEROTOXIGENIC ESCHERICHIA-COLI/

A monoclonal antibody (MAb 84) raised against the dissociated CFA/I fi mbriae of enterotoxigenic Escherichia coli was characterized with rega rd to antigen binding and epitope specificity. Enzyme-linked immunosor bent assay (ELISA) showed that MAb 84 had higher affinity to CFA/I sub units than to intact CFA/I fimbriae and recognized a Salmonella flagel lin carrying an insert corresponding to amino acids 32 to 45 of the CF A/I subunit, Fine epitope mapping based on the Pepscan technique showe d that the peptide (TFESY43)-T-39, derived from the sequence of the ma ture CFA/I subunit, was specifically recognized by MAb 84, The (TFESY4 3)-T-39 sequence is probably not accessible an the surface of the nati ve CFA/I fimbriae since MAb 84 did not bind to intact fimbriae as eval uated in inhibition ELISA tests. Moreover, MAb 84 did not agglutinate fimbriated ETEC cells nor inhibit CFA/I-mediated hemagglutination or t he adhesion to Caco-2 cells.