Conjugate vaccines against group B Streptococcus types IV and VII.

Although rarely encountered, group B Streptococcus (GBS) types IV and VII have been isolated from infants and adults with invasive disease. This study was designed to determine the immunogenicity and efficacy in animals of conjugate vaccines prepared with GBS types IV and VII capsular polysaccharide (CPS). Despite the striking similarities in structure of these 2 carbohydrate antigens, high-titer rabbit antiserum to each conjugate vaccine was serotype specific. Active vaccination of female mice with the conjugate vaccines induced type-specific IgG and resulted in survival of >90% of newborn pups challenged with viable GBS of homologous serotype. If needed, types IV and VII CPS conjugate vaccines of the design described can be added to the formulation of a multivalent GBS vaccine.