CHARACTERIZATION OF A 20-KDA PILUS PROTEIN EXPRESSED BY A DIARRHEOGENIC STRAIN OF NON-O1 NON-O139 VIBRIO-CHOLERAE/

A diarrheogenic strain of non-O1/non-O139 Vibrio cholerae (10325) belo nging to serogroup O34 was earlier shown to express a new type of pilu s composed of a 20-kDa subunit protein. Amino-terminal sequence data ( determined up to 20 amino acid residues) of this protein showed it to be different ii om the subunit proteins of other known types of pill o f V. cholerae. On the other hand, it showed complete homology with the corresponding sequence of a 22-kDa outer membrane protein (OmpW) of V . cholerae. Expression of 10325 pill was Favored in AKI rather than in NE medium and at 30 degrees C rather than at 37 degrees C. Further, c ultural conditions favoring pilus expression also enhanced autoaggluti nation and adherence properties of strain 10325. An antiserum to the 2 0-kDa protein induced passive protection against challenge with the pa rent organism 10325, bur not against V. cholerae O1 strains. Such prot ection was shown to be mediated by inhibition of intestinal colonizati on in vivo. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V.