Outer membrane proteins of Shigella sonnei. II. Comparative studies on virulent and avirulent strains of phase I.

The proteins of the outer membrane of virulent and avirulent Shigella sonnei phase I strains were characterized by SDS-polyarcylamide gel electrophoresis and their molecular weights determined. Significant quantitative differences were found in composition of the outer membrane proteins between virulent and avirulent strains. These differences were confirmed in electrofocusing experiments and disc-crossed immunoelectrophoresis.