A test of antigenicity for the selection of strains for inclusion in cholera vaccines.

The antigenicity of a large number of cholera vibrio strains was compared, in groups of rabbits, by evaluating the serological responses to single limited doses of vaccines prepared from the strains. On the basis of these tests, it was possible to construct 2 quadrivalent (El Tor and classical, Inaba and Ogawa) vaccines which differed significantly in antigenicity for rabbits but which were indistinguishable in the "standard" mouse-protection test. The advisability of using a test of antigenicity for selection of strains and laboratory evaluation of vaccines is considered. Application of the proposed antigenicity test would depend on further comparisons of human response to vaccines which differ in antigenicity for the rabbit.