Identification of H-specific determinants in flagellin of four Escherichiacoli strains

The H serogroup of Escherichia coli is determined by the flagellar antigen, flagellin. Sequence analysis of the flagellin gene, fliC, reveals a centra l variable region and the highly conserved N- and C-termini. This variable region has been shown to encode both H-specific and cross-reactive epitopes . Using polyclonal antibodies, we mapped the linear H-specific determinants in flagellin from four E. coli serotypes O157:H10, O138:H14. O157:H42 and O157:H43. The specificity of all potential fragments was verified with 52 E CRC (Escherichia coli Reference Center) H-specific antisera. Our results in dicated that: (a) a specific determinant of H10 flagellin (1263 bp long) ma ps to the region covering amino acid residues 305-331; (b) a specific deter minant of H14 flagellin (1653 bp long) maps to the region covering amino ac id residues 430-461: (c) a specific determinant of H42 flagellin (1281 bp l ong) maps to a region covering amino acid residues 171-201; and (d) a speci fic determinant of H43 flagellin (1506 bp long) maps to a region covering a mino acid residues 200-260.