[The effect of the synergistic action of enterotoxin on the specific protective complex of Shigella sonnei]. / Effekt sinergentnogo deistviia énterotoksina na spetsificheskii protektivnyi kompleks Shigella sonnei.

The study has first established that enterotoxin enhances the protective potency of S. sonnei specific protective complex. This effect has been revealed both in experiments of the oral immunization of mice and in experiments of the conjunctival immunization of guinea pigs and depends on the dose of enterotoxin used in the experiment. The increase of protection has a specific character. These observations open prospects for further enhancement for the protective properties of S. sonnei specific protective complex, which should be taken into consideration in developing the vaccinal preparation.

[The diagnostic value of a meningococcal-B erythrocyte diagnostic agent based on the group-specific polysaccharide]. / Diagnosticheskaia tsennost' meningokokkovogo éritrotsitarnogo B-diagnostikuma na osnove gruppospetsificheskogo polisakharida.

In this work the diagnostic value of group B meningococcal erythrocyte diagnosticum was determined. 585 blood serum samples taken from adult donors were studied: 220 samples from practically healthy persons and 365 samples from 144 patients with meningococcal infection and purulent bacterial meningitis of nonmeningococcal etiology. Group B meningococcal erythrocyte diagnosticum was found to possess serological activity and to reveal the growth of specific antibodies in the sera of patients with meningococcal infection, serologically confirmed by the isolation of group B meningococcal culture, in 100% of cases on weeks 2-3 of the disease. Diagnostic characteristics--specificity and sensitivity--for group B erythrocyte diagnosticum were, respectively, 90.2% and 63.5%. The study revealed that antibodies to several group-specific meningococcal polysaccharides in blood sera can be simultaneously determined in the passive hemagglutination test with a set of erythrocyte diagnostica, which should be taken into consideration in the clinical interpretation of serological results.

[Protective properties of Vi-antigen preparations as dependent on their adhesin content]. / Protektivnye svoistva preparatov Vi-antigena v zavisimosti ot soderzhaniia v nikh adgezina.

Adhesins contained in the preparation of Vi-antigen have been found to enhance its immunogenic and protective properties. In the preparations of Vi-antigen obtained from Salmonella typhi and Citrobacter freundii the presence of two antigenic determinants has been revealed. One of them is associated with the Vi-receptor and the other determinant, with adhesin. Both determinants take part in the protection of mice from Salmonella infection.

[Immunogenic complexes of the soluble surface antigens of Sh. sonnei]. / Immunogennye kompleksy poverkhnostnykh rastvorimykh antigenov Sh. sonnei.

The comparative study of the immunogenic properties of Sh. sonnei (phases I and II) soluble surface antigens obtained by the modified method of aqueous-saline extraction and Sh. sonnei (phase I) antigen obtained by Boivin's method was made with the use of the keratoconjunctival test in guinea pigs. The protective activity of a high molecular fraction obtained by the fractionation of phase I soluble surface antigens in Sepharose 4B was studied. Boivin's antigen, when used for immunization in optimum doses, was found to have pronounced protective properties, whereas phase II soluble surface antigens showed no protective activity. A high molecular fraction obtained from phase I soluble surface antigen was found to be the most immunogenic. Protective activity was largely connected with protein antigen. The question whether protein antigen was an independent protective antigen or whether it constituted a part of a complex which determined the protective activity of a high molecular fraction remained unsolved.

[Immunochemical findings about the high molecular weight surface antigens of Shigella sonnei]. / Nekotorye immunokhimicheskie dannye o vysokomolekuliarnykh poverkhnostnykh antigenakh Shigella sonnei.

The authors studied immunochemical properties of the high molecular fraction of surface soluble antigens obtained by extraction with salt solutions from Sh. sonnei (virulent strain 1041) dried with acetone. The high molecular fraction was isolated by gel-filtration on Sepharose-4B. Along with the O-somatic antigen, this fraction contained thermostable and thermolabile antigens resistant to trypsin and RNA-ase treatment, and also protein-containing antigens disintegrated by trypsin. In difference from the O-somatic antigen, one of the thermostable components was completely precipitated with 50% alcohol.

[Soluble surface antigens of virulent Sh. sonnei]. / Poverkhnostnye rastvorimye antigeny virulentnykh Sh. sonnei.

The authors conducted an immunochemical analysis of the surface soluble antigen preparations (SSAP) obtained by extraction with physiological saline of the virulent Sh. sonnei microbes killed with acetone. Immunochemical studies by the immunoelectrophoresis and immunodiffusion methods in agar gel, separation on sepharose 4B and in polyacrylamide gel showed the presence of 3 groups of the antigens in the SSAP composition: 1) protein antigens, determining the commonness with the Sonne microbes of the II phase and intergenera associations with typhoid and enteropathogenic E. coli; 2) specific somatic antigen of the Boiven type present in small amounts in the SSAP; 3) specific antigens differing by specificity from the Boiven antigen detected in the microbes of the I phase only and possibly playing a role in the virulent and immunogenic properties of the causative agent.