Conversion of Type Antigen IV in Shigella Flexneri by Bacteriophage

Abstract

It was found that in Shigella flexneri strains 1 to 4, a temperate phage induced antigenic conversion, not only from 1a to 4a (I→IV) and from 3b to 4b (III→IV), as reported by Matsui (1958), but also from 1b to 4b (I→IV) and from 2a to 4a (II→IV). In these cases, the conversion was performed with respect to IV₁ of antigen IV, but not to IV₂. The phage which induced these conversions could be demonstrated in 4c (EW 19) as well as in 4b (EW 18), exhibiting an affinity to group antigen 4. Further, variant Y from 1a and 2a was sensitive to this phage, and when lysogenized by it, came to possess antigen IV₁. However, from standard strain Y (EW 13), which could adsorb this phage, it was impossible to obtain any bacteria which came to possess antigen IV₁.