[Detection of autoimmune changes in white mice as a method of studying the biological properties of Shigella sonnei].

An attempt was made of using for the purpose of studying the virulence of Sh. sonnei of the method of determination of autoimmune plaque-forming cells in infected albino mice. By the mentioned method a total of 231 strains of Sh. sonnei of various biochemical types were examined. The virulence of 103 strains was checked in paralled by the keratoconjunctival test. It was shown that the method of determination of the autoimmune plaque-forming cells in the blood of infected mice could be used as a test for the virulence of Sh. sonnei, which was more sensitive than the keratoconjunctival test. Among the cultures studied 14.7% proved to be avirulent, 51.5%-of low virulence, 21.2%-moderately virulent, and 12.6%-highly virulent. Strains of the II biotype proved to be the most virulent, and strains of the III biotype-the least. The virulence of the cultures isolated from the patients with acute dysentery was more than double that of the cultures isolated from persons who came in contact with the patients.