[Bacterial antigenic structure of Shigella flexneri serotype 1B and its 3B serotype mutant and susceptibility to bacterial action of complement in normal bovine serum].

The susceptibility of S. flexneri 1b and 3b strains to killing action of serum was investigated. Differences in sensitivity to bactericidal action of complement appeared to result from different structure of their LPS-es. The protective effect of LPS-es depends both on their origin and concentration.