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L K Stepanova

Publications and source records attributed to L K Stepanova.

At least 19 recordsLinked to original sources
PubMed1992

[The safety of a new chemical typhoid preparation containing a complex of Vi and K antigens in tests of its acute and chronic toxicity].

Acute and chronic toxicity of a new chemical typhoid preparation containing the complex of surface Vi- and K-antigens has been studied. The study has revealed that the preparation, when introduced subcutaneously and intravenously in immunizing doses in a single injection or in multiple injections, produces no toxic effect on the organs and tissues of experimental animals. In experiments of chronic toxicity the microscopic study has shown pronounced hyperplasia of the lymphoid system with enhanced macrophage reaction in the spleen, thymus, mesenteric lymph nodes and Peyer's patches in the small intestine.

Animals↗
PubMed1985

[Antigenic structure of Salmonella L forms studied by an immunoferritin method].

The antigenic structure of the L-forms of salmonellae (S. typhimurium and S. typhi) in comparison with that of the initial bacterial cultures and revertant cultures was studied with the use of the immunoferritin method. The L-forms of salmonellae were found to retain an insignificant amount of O-antigen, as well as to have K-antigen on the surface of the cytoplasmic membrane, but in a lesser amount than the initial strains. In the cultures reverting from the L-forms of S. typhimurium and S. typhi the quantitative and qualitative characteristics of O- and K-antigens were completely restored.

Animals↗
PubMed1985

[Mapping of the genetic determinant controlling Salmonella K-antigen synthesis. II. Nonmotile mutants of Salmonella typhimurium].

According to the preliminary data, S. typhimurium K-antigen is located in the area of minutes 40-44 on the Salmonella chromosome map. The formation of nonmotile mutants from motile Salmonella strains was induced by the action of nitrosoguanidine. Two main groups of mutants differing in their reaction of agglutination with H- and K-antisera were obtained: Mot-H-K- (motA or motB mutants) and Mot-H-K- (H1- or fla- mutants). The transduction transfer of the sign of motility by phage P22HT to H-K- mutants and to H1- and flaE- mutants led to the restoration of agglutination ability with respect to H- and K-antisera in all Mot+ transductants under study simultaneously. The restoration of H+K+ phenotype was also observed in spontaneous motile revertants obtained from H-K- mutants. Thus, the gene controlling the synthesis of K-antigen in Salmonellae was shown to be incorporated into the Fla operon, the regulatory system of the operon controlling the expression of this gene.

Antigens, Bacterial↗
PubMed1983

[Immunoelectrophoretic analysis of the antigenic composition of Salmonella typhi in the process of L transformation and reversion].

In the study of the antigenic composition of S. typhi L-forms and their revertants were determined. The stable L-forms were characterized by profound disturbances in the synthesis of Vi- and H-antigens. After reversion to bacterial forms all the revertants under study showed the complete restoration of their bacterial antigenic structure.

Antigens, Bacterial↗
PubMed1983

[Mapping of the genetic determinant controlling Salmonella K-antigen synthesis. I. Localization of the determinant in conjugation experiments].

The preliminary data on the localization of the gene responsible for the synthesis of K-antigen in salmonellae were obtained. Using Salmonella Hfr donors with different onset of the transfer of chromosomal markers and with phenotype K+, the authors selected different classes of recombinants in the process of their crossing with K- recipients. The positive result of the agglutination test with specific K-antiserum indicated that the transconjugate thus obtained possessed phenotype K+. The gene responsible for the synthesis of K-antigen was shown to be localized between minutes 46 and 41 of the genetic map of S. typhimurium. This gene was not cotransduced with the histidine marker localized on minute 44 of the map.

Antigens↗
PubMed1979

Surface K antigen in Salmonella paratyphi B.

It was established by agar immunoelectrophoresis that Salmonella paratyphi B lysate contains a large number of soluble antigens which display a varying degree of serological specifity as well as different diffusion and electrophoretic mobility. Salmonella paratyphi B was found to possess, apart from specific O and H antigens, a surface K antigen. This is a distinct antigen having strict serological specificity. Purified K antigen displayed anodic mobility in immunoelectrophoresis. A detailed study of K antigen properties in cultures treated by different methods as well as immunochemical investigations of purified K antigen showed that the surface K antigen of S. paratyphi B differs from its O, M, Vi, H and other known antigens in terms of basic characteristics.

Agglutination↗
PubMed1978

[Parathyphoid B-antigen containing a complex of protective surface antigens].

The authors obtained a complex antigen from paratyphoid B bacilli containing complete O-, K- and H-antigens. The preparation was nontoxic and was characterised by marked antigenic properties. In intravenous and oral administration it stimulated production of specific O-, K-, and H-antibodies in high titres. Complex paratyphoid B antigen possessed a marked protective activity and provided intense immunity in subcutaneous and oral administration to experimental animals.

Administration, Oral↗
PubMed1978

[Reactogenicity and immunological effectiveness study of a complex paratyphoid B antigen].

Reactogenic property and immunological efficacy of the paratyphoid preparation containing a complex of O-, K- and H-antigens obtained by single-stage antigens extraction were studied in a limited group of volunteers (22 persons). The antigen gave no untoward reactions and proved to be safe when given orally in doses of 25 to 150 mg. Paratyphoid B antigen was characterized by a marked immunization activity and stimulated formation of specific paratyphoid O-, K- and H-agglutinins and antibodies of the IgA,- IgG,- and IgM-classes.

Agglutinins↗
PubMed1977

[Relationship between the presence of K- and O-antigens and the behavior of salmonellae in a culture of macrophages].

It was shown on experimental models (mice and in kerato-conjunctival reaction) in comparative study of spontaneous stable salmonella mutants that disturbances in the process of synthesis of K- or O-antigens led to the weakening or the loss of the bacterial virulence. In the study of the behavior of the salmonella mutants it was revealed in the culture of phagocytizing macrophages that a reduction of the cytotoxic action of bacteria was connected with the changes of the somatic O-antigen, whereas the capacity of salmonella to reproduction inside the macrophages correlated with the presence of surface K-antigen.

Animals↗
PubMed1977

[Strains of salmonella with altered antigenic structure].

The authors studied 260 freshly isolated and laboratory cultures of salmonellae belonging to different serological groups. Heterogeneity of the majority of the strains studied by colour fluorescence of the colonies in the oblique light flux was demonstrated. Genetically bound spontaneous stable mutants with a different antigenic composition were selected by this method from a number of serological types. The isolated mutants were in the S-form and failed to differ by morphological, cultural and biochemical properties from the initial parental strains. A study of the antigenic structure by the method of agar immunoelectrophoresis and determination of their serological properties showed the mutants to have disturbances in the processes of O- or K-antigen synthesis.

Antigens, Bacterial↗
PubMed1975

[Study of the antigenic structure of Salmonella by means of immunoelectrophoresis].

The method of immunoelectrophoretic analysis was applied to the study of the antigenic structure of 180 freshly-isolated and laboratory cultures of salmonellae belonging to 29 serological types. A complicated set of specific and common antigens of bacteria was revealed in direct and cross experiments with the use of homologous and heterogenous antisera; immunophoregrams were drawn for each of the serological type under study. General regularities in immunophoretic, diffuse and serological characteristics of the individual antigens of salmonellae were established. It was shown that different serological types of salmonellae possessed surface K antigens along with the O and H antigens. On immunophoregrams K-antigens of salmonellae were revealed in the form of a bright precipitation arch in the central or the anode zone; O antigens gave a characteristic two-component precipitation line in the cathode zone of the phoregram.

Antigens, Bacterial↗