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. MATERIALS AND METHODS: Strains of Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus agalactiae were used in the study. Array of used methods included opsonophagocytic test as well as active and passive protection of experimental animals against streptococcal infection. RESULTS: It was shown that antibodies specific to studied polypeptides opsonized several strains of group A and B streptococci as well as pneumococci. Immunization of mice with ScpB1 polypeptide resulted in more rapid recovery of animals from challenge systemic group B streptococcal infection. Antisera specific to both polypeptides provided passive protection of animals from infection caused either GBS or GAS. CONCLUSION: Obtained data confirm the feasibility to use recombinant fragments of several GBS conservative proteins in vaccine for induction of protection against infections caused by different species of pathogenic streptococci.