[Degree of purification of a chemical epidemic typhus vaccine of the heterogeneous ballast proteins].

The degree of purification of chemical typhus vaccine from the ballast proteins of the substrate has been studied by chemical and immunochemical methods. The analysis of 11 production batches of the vaccine and a number of model preparations has revealed that chemical typhus vaccine is completely free from nonprotein nitrogen-containing components and, to a considerable extent, purified from ballast protein, its concentration being 0.033-0.242 mg per vaccination dose, and also possesses a high specific activity (198-1454 antigenic units per mg of protein. Ballast proteins include at least 5 egg antigens. The concentration of one of them varies between 0 and 5 micrograms per dose. A number of recommendations is made; their realization will make it possible to increase the degree of purification of chemical typhus vaccine.