Persistence of functional antibodies to group B streptococcal capsular polysaccharides following immunization with glycoconjugate vaccines

The duration of functional activity of group B streptococcal (CBS) glycoconjugate vaccine-induced capsular polysaccharide-specific (CPS) IgG was evaluated among healthy adult responders. Opsonophagocytic activity declined significantly from a 4-week post-immunization peak, but substantial functional activity, exceeding 1 log(10) reduction in CBS cfu/mL, was retained at 18 months to 2 years post-immunization for each CBS type assessed. The persistence of functional antibody activity when CBS CPS-specific IgG concentrations decline, although remaining significantly higher than pre-immunization levels, suggests that long-term protection may be expected from candidate CBS glycoconjugates administered to this population. (C) 2012 Elsevier Ltd. All rights reserved.