Studies on Directed Variation of Salmonella 0-15 and 0-34 by Bacteriophage [Ii]

Antigen transformation of strains which have antigenic structure of subgroup E3 was performed with 0-15 and 0-34 antisera. The 0-15 antiserum transformed 0-(3). (15). 34 into 0-3.10, and the 0-34 antiserum transformed 0-(3), (15). 34 into 0-3.15. It was further found that when these variants were infected with the respective phage (ε15 or ε34) they were lysogenized and the original antigenic structures were restored.Considering the results in reports 1 and 2, the antigen transformation by two kinds of phage from 0-3.10 into 0-3.15 and from 0-3.15 into 0-(3). (15). 34 can not be explained by spontaneous mutation selection. And further, comparative investigation of various phenomena respectively indicated by the names of transformation, recombination and transduction, leads us to consider that antigen transforming factor is the bacteriophage itself.Though ε15 and ε34 are unrelated either biochemically or serologically, they are dependent each other as the antigen transforming factor. Namely, ε34 can transform antigenic structure of subgroup E2 into that of subgroup E3, and those of E1 and E4 into that of E3, not directly but twostops-wise by the intermediation of ε15.Strains having the antigenic structure of subgroup E3 is doubly lysogenic bacterium, and the prophages of ε15 and ε34 which are contained in the cell seem to govern the production of antigen 0-15 and 0-34, respectively.