Sh. dysenteriae serotypes2,4,8-immunochemistry and phage receptor activity

Among three analyzed serotypes of Shigella dysenteriae, namely, the serotypes 2,4 and 8, the serotype 2 proved to be a strong immunogen in rabbits, inducing anti-polysaccharide antibodies as well as antiprotein antibodies in all the animals. In contrast, the serotypes 4 and 8 were weak immunogens and among the rabbits some have synthesized only anti-proteins while others had antibodies against the somatic conjugate. Aside from the somatic antigens, large amounts of proteins were isolated from all the strains; however, the numerous determinants of these proteins were proven with the help of a serum to proteins from Sh. sonnei. The polysaccharides were specific for the serotype. The sensitivity of Sh. dysenteriae strains to phage P1 and the phage receptor actigity of different bacterial extracts were examined. By using the phage receptor neutralization test, it was possible to demonstrate that the receptor substance is a common component present in the lipopolysaccharide. The nature of neutralization has been discussed.