[Study of genetic control of synthesis of type III and 6th group-specific antigens of Flexner shigellae].

As revealed in experiments of interspecific and intraspecific crosses, the determinant responsible for the group-specific 6, as well as controling the synthesis of type III antigens of Sh. flexneri were localized near the lac-pro markers on the chromosome. In intraspecies crosses of bacteria of y variant with the donor Sh. flexneri 3c strain the percentage of linking of lac+a6+ was 32, and of lac+aIII+ --24. Genetic confirmation of the dependence of the function of the a6 (defined as att6) determinant on the presence of an antigenic complex 3,4 and of the association of the serological detection of the antigen III on the gene a6 was presented. On the basis of the data of Gemski et al it can be supposed that the determinant of the a6 served as the site of attachment of a specific converting phage.