[Recombinant fragments of conservative proteins of group B streptococci as a basis of specific vaccine].

Aim: The study devoted to problem of using of recombinant fragments of group B streptococci (GBS) conservative proteins for induction of immune response against streptococcal infections. Two recombinant polypeptides (ScaAB and-ScpB1) corresponding to immunogenic epitopes of two surface GBS proteins ScaAB and C5a-peptidase, which are presented in other streptococcal species, were studied. The objective of the study was to assess specificity and protective activity of mentioned polypeptides against homologous and heterologous strains of pathogenic streptococci from different groups.

[Comparative study of experimental conjugated and combined vaccines against group B streptococci].

Immunogenic properties of recombinant protein ScaAB mixed with polypeptide P6 as well as conjugate of the former with capsular polysaccharide type III (PSIII) were assessed. Protein-polysaccharide conjugate was synthesized by reductive amination method. Immunogenicity was studied on the mouse model using aluminium hydroxide as adjuvant.

[Protective properties of certain external proteins of group B streptococci].

On the basis of genes, which control synthesis of externally localized proteins of group B streptococci (bac and scaAB), recombinant polypeptides P6 and ScaAB were obtained. Data on protective activity of these polypeptides during experimental infection of immunized mice as well as in opsonophagocytic test on cultivated peritoneal macrophages are presented. It has been shown that protective effect of specific antibodies to P6 was dependent from intensity of immune response.

[Immunogenicity of modified by dextran recombinant fragment of Bac protein of group B streptococci].

Opportunity to increase of immunogenicity of recombinant polypeptide P6 constructed on the basis of surface protective Bac protein by its chemical conjugation with dextran (D) 40 was studied. 3 preparations with different quantity of protein and polysaccharide components were obtained. Their testing with standard serum showed that antigenic determinants of the polypeptide were preserved although partly enclosed and structure of antigenic determinants did not significantly changed.

Analysis of recombinant group B streptococcal protein ScaAB and evaluation of its immunogenicity.

Group B streptococcal (GBS) gene encoding the putative lipoprotein and adherence factor ScaAB was cloned and expressed in E. coli. Recombinant ScaAB protein was isolated.