[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.

[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.

[Comparative evaluation of the immunological activity of new typhoid vaccines with established prophylactic effectiveness (data from a controlled experiment)]. / Sravnitel'naia otsenka immunologicheskoi aktivnosti novykh briushnotifoznykh vaktsin s ustanovlennoi profilakticheskoi éffektivnost'iu (dannye kontroliruemogo opyta)

The authors present the results of studying the immunological efficacy of a dry alcoholic typhoid vaccine enriched with S. typhi Vi-antigen in the assessment of this vaccine in controlled epidemiological trial during the immunization of children aged 7--8 years. O- and Vi-antibodies were tested in the reaction of hemagglutination, H-antibodies--in the agglutination reaction with the microbial diagnostic agent, the properties of antibodies--in a test with cystein, and bactericidal properties of the sera--against the virulent S. typhi strain. Examination of 355 coupled sera obtained before and 3 weeks after the immunization demonstrated a high level of Vi-(1:47) and of the O-(1:580) antibodies and high bactericidal properties of the sera in persons vaccinated with the alcoholic vaccine enriched with the S. typhi Vi-antigen. The results obtained and the data on the formation of prolonged immunity following a simgle immunization suggested that a high protective effect was caused by a combined action of the O- and Vi-antigens contained in the vaccine in optimal doses.