[Cholera vibrio fractions. I. Isolation of alkaline extracts of cholera vibrios and a study of their biological properties].

The authors suggest a well-reproducible method of preparation of a biologically-active fraction of an alkaline extract of cholera vibrio from the strain 569B of Inaba serological type consisting in a preliminary triple removal of endotoxin (O-antigen) of the causative agent from the microbial cell suspension with trichloracetic acid with the subsequent extraction of the microbial mass and neutralization of the extract obtained capable of effective detection of the state of specific sensitization of the organism to cholera vibrio. Preparations of the alkaline extracts (cholera allergen) obtained were standard by chemical composition, they were characterized by a high protein content (up to 77%) and were practically nontoxic. These preparations can be used as a bacterial allergen for the experimental investigations.