Characterization of the pili isolated from Vibrio parahaemolyticus O3:K6.

Pilus of Vibrio parahaemolyticus O3:K6 strain LVP9 belonging to the newly identified clone was purified and characterized. The molecular mass of the pilin was estimated to be about 18 kDa by SDS-PAGE, and the isoelectric point of the pilin was 5.0 +/- 0.2. The LVP9 pili were antigenically different from the other V. parahaemolyticus Na2 pili and Ha7 pili as previously reported, nevertheless all three had indistinguishable morphology and shared a high degree of homology in their N-terminal amino acid sequences. Strain LVP9 and its purified pili did not agglutinate human and rabbit erythrocytes. The LVP9 organisms and the purified pili were adhesive to the rabbit intestine. The adhesion was inhibited by pretreatment of the rabbit intestine with the purified pili or by pretreatment of the organisms with the Fab fractions of anti-pilus antibody. These results indicate that the LVP9 pilus is an adherent factor to the rabbit intestine.