IMMUNOGENICITY AND PROTECTIVE ACTIVITY IN ANIMALS OF A TYPE-V GROUP-B STREPTOCOCCAL POLYSACCHARIDE TETANUS TOXOID CONJUGATE VACCINE

The recent recognition of type V strains as a frequent cause of group B streptococcal (GBS) infection in both infants and adults prompted investigation of an effective vaccine against these organisms. Purified GBS type V polysaccharide was covalently linked to tetanus toroid to form a type V polysaccharide-tetanus toroid conjugate vaccine. The conjugate elicited type V polysaccharide-specific IgG antibodies in rabbits, while unconjugated type V polysaccharide did not. Conjugate-induced rabbit antibodies were opsonic in vitro and protected mice against challenge with type V GBS. Efficacy of the conjugate vaccine also was demonstrated in a maternal vaccination/neonatal challenge model in mice. A GBS type V polysaccharide-tetanus toroid conjugate is an effective immunogen in animal models and may be a useful component for inclusion in a multivalent GBS vaccine for human use.