Behavior of a surface antigenic determinant of lateral flagella of Vibrio parahaemolyticus.

The behavior of a surface antigenic determinant (SA) of lateral flagella of Vibrio parahaemolyticus was studied. SA, located on the surface of flagellar filaments, is responsible for H-agglutination and specific for serotype. Results of H-agglutination inhibition tests demonstrated that SA could not be detected on the flagellin molecule when the flagellar filaments were dissociated to flagellin monomers by heating or treatment with urea, sodium dodecyl sulfate, HCl, or acetone, although SA could be detected on short flagellar fragments obtained by milder heat treatment. When flagellar filaments were reconstituted from flagellin monomers, SA was detected on the surface of the filaments. These results suggest that SA is buried in the flagellin molecule with dissociation of flagellar filaments to flagellin monomers or steric configuration of SA itself is altered to a different form which cannot react with the responsible antibody.