Mapping of Escherichia coli H27-specific epitope from H-specific polypeptides

A murine monoclonal antibody (MAb) reactive to H27 flagellin antigen was pr oduced and characterized. Forty-nine partially purified native H-type flage llins were used to evaluate the specificity of the MAb. The fliC gene of H2 7 is 1,464 bp in length (487 amino acids [aa]; 50.88 kDa). The central vari able region (CVR) of the H27 flagellin gene was defined by comparison with flagellin sequences derived from H8, H34, and H49. To study the distributio n of antigenic epitopes, the CVR covering amino acid residues 70 to 457 (38 8 aa) was dissected into seven overlapping fragments. Fragments carrying th e H-type-specific antigenic determinants were identified by R27-specific an tiserum. Polyclonal antibodies raised against different H-type flagellin pr oteins were used to determine the cross-reactive determinants. Three fragme nts, spanning amino acid residues 240 to 380, which carried the potential H -specific determinants were used for MAb production. A MAb specific to H27 was produced, and the specific epitope was mapped to amino acid residues 33 0 to 340. In this study, we produced MAbs from predetermined H27-specific p olypeptides and used whole flagellin in enzyme-linked immunosorbent assays to circumvent the interference of anti-glutathione S-transferase antibodies . These factors when combined could help to improve the identification of t he desired MAb.