Studies on bacteriophage. II. Inhibition of lysis of Escherichia coli B by the somatic antigen of Phase II Shigella sonnei.

By serological means it has been shown that E. coli B contains an antigen closely related to the protein-lipocarbohydrate complex of Phase II Sh. sonnei. Lysis of E. coli B by three of the T viruses, T(3), T(4), and T(7), can be inhibited by the Phase II dysentery antigen. It has been suggested that the receptor of E. coli B with which these viruses combine is this newly described antigenic component. Two variants of the virus T(3) have also been described, in stocks which have been treated with the Phase II antigen. One of these variants infects both Phase II Sh. sonnei and E. coli B, and the other infects only the latter microorganism; neither of the two variants is inhibited by concentrations of the Phase II antigen of 1 mg. per cc. The distinctive properties of the variants are not hereditary.