Antigenic analysis of vibrio culture filtrate and vaccine El Tor vibrio

Abstract

The antigens present in the preparation of cholera toxin consisting of the culture filtrate of 569 B strain of V. cholerae have been analysed by gel-diffusion, intra-gel absorption, and immuno-electrophoresis. The antiserum raised against the toxin was tested using the following antigens: whole cell lysates of V. cholerae 569 B and an El Tor (water) strain W 6 (proposed as a vaccine strain), suspensions of the same strains of vibrios with and without heat-denaturation, suspension of an El Tor (case) strain (GS-9) and a preparation of vibrio polysaocharide. The antitoxic serum gave four precipitin bands against the toxin preparation and nine bands against the whole cell lysate of V. cholerae. Two bands could be identified as being due to the heat-labile specific antigens present in the cholera toxin. These two bands were abolished on absorption of the antitoxic serum with a live suspension of W 6 but not on absorption with heat-denatured W 6. It has, therefore, been concluded that the proposed vaccine strain W 6 contains the specific antigens of cholera toxin. The significance of these results has been discussed in relation to the residual virulence of the proposed vaccine strain and antitoxic immunity produced in the intestinal tract of the adult rabbit following exposure to the vaccine strain.