Synthesis and preclinical evaluation of glycoconjugate vaccines against group B Streptococcus types VI and VIII

Group B Streptococcus (GBS) types VI and VIII are prevalent among serotypes isolated from pregnant women in Japan. Maternal vaccination with a safe an d effective GBS vaccine has been proposed as a rational approach to prevent neonatal GBS disease. Because antibody specific for the capsular polysacch aride (CPS) antigens of GBS is protective, vaccines were developed with pur ified type VI and VIII CPS coupled to tetanus toroid. In rabbits the newly synthesized conjugate vaccines elicited high-titered, type-specific antibod y that was opsonically active in vitro. Moreover, litters born to mice acti vely vaccinated with the conjugate vaccines, in contrast to uncoupled CPS o r saline, were protected against an ordinarily lethal challenge of GBS of h omologous serotype. GBS types VI and VIII conjugate vaccines of the design presented may be important components of a multivalent GBS vaccine for use in regions where these serotypes predominate.