Investigation of the antigenic composition of the cells and the exotoxin of Sh. dysenteriae (Shiga) by agar immunoelectrophoresis and polyacrylamide gel disc electrophoresis.

Using the method of immunoelectrophoresis in agar, we established the presence of 12 soluble antigens in Sh. dysenteriae (Shiga). We differentiated among them 3 specific antigens situated in the cathodic region. One of them is the somatic O antigen while the other two are thermolabile surface K antigens of these bacteria. K antigens of Grigoryev-Shiga bacteria differ from the earlier described K antigens of the Newcastle and Boyd Shigellae in their positive electric charge, in greater lability in relation to temperature and chemical effects and evidently also in their chemical character. The remaining protein antigens are common for either the genus of Shigella or for the family of enterobacteria. The exotoxin preparation isolated from the R strain of Sh. dysenteriae (Voile 30) by precipitation with trichloroacetic acid is represented in the immunophoreogram by five precipitation lines. Disc electrophoresis in polyacrylamide gel made possible the investigation of the composition of the exotoxin and isolation of the two fractions responsible for its toxic effect. The method of preparative electrophoresis in polyacrylamide gel can evidently be used for obtaining purified Sh. dysenteriae exotoxin preparations.