Type-specific protection of neonatal rats from lethal group B streptococcal infection by immune sera obtained from human volunteers vaccinated with type III-specific polysaccharide.

AUTOR(ES)

De Cueninck, B J

RESUMO

Sera obtained from human volunteers at 6 weeks after vaccination with highly purified type III polysaccharide antigen prepared from a group B Streptococcus, strain M732, were found to protect neonatal rats from otherwise lethal infection by the homologous strain. The specific antibody content of the sera, expressed in micrograms of antibody protein per milliliter, was determined by an enzyme-linked immunosorbent assay in conjunction with quantitative precipitin analysis. For two sera studied in detail, the protective dose of antibody for 50% of the animals was 0.4 micrograms. Immune serum obtained from a volunteer who received type II polysaccharide vaccine was not protective against type III infection. Absorption of anti-type III serum by quantitative precipitation of antibodies with type III polysaccharide completely removed the passive protective activity of the serum. The results show that antibodies induced in humans by purified type II polysaccharide give serotype-specific protection in an animal model of neonatal infection.

Documentos Relacionados

• Soluble group- and type-specific antigens from type III group B Streptococcus.
• Type-specific capsular antigen is associated with virulence in late-onset group B Streptococcal type III disease.
• Quantitation of in vitro opsonic activity of human antibody induced by a vaccine consisting of the type III-specific polysaccharide of group B streptococcus.
• Detection of group B streptococcal antibodies in human sera by radioimmunoassay: concentrations of type-specific antibodies in sera of adults and infants infected with group B streptococci.
• Isolation and characterization of type III group B streptococcal mutants defective in biosynthesis of the type-specific antigen.