Gold nanoparticles as carriers for a synthetic Streptococcus pneumoniae type 14 conjugate vaccine.

Aims: Coupling of capsular polysaccharides of pathogens to immunogenic protein carriers (conjugate vaccines) improves carbohydrate immune response. Our idea is to explore gold nanoclusters as carriers to prepare fully synthetic carbohydrate vaccines.

Materials & Methods: Gold glyconanoparticles bearing a synthetic tetrasaccharide epitope related to the Streptococcus pneumoniae type 14 capsular polysaccharide (Pn14PS), the T-helper ovalbumin 323-339 peptide (OVA(323-339)), and D-glucose were prepared by a one-pot method.

Antibody- and cell-mediated immune responses to a synthetic oligosaccharide conjugate vaccine after booster immunization.

Memory formation to CRM-neoglycoconjugate, a synthetic branched tetrasaccharide of Streptococcus pneumoniae type 14 polysaccharide (Pn14PS) that is conjugated to a CRM197 protein, was investigated using mice models. Mice were first immunized with the CRM-neoglycoconjugate and then boosted with either the same neoglycoconjugate or a native Pn14PS in order to investigate the effect of booster immunization. Boosting with the CRM-neoglycoconjugate resulted in increased levels of interleukin 5 (IL-5) in the serum on Day 1, followed by the appearance of high levels of specific anti-Pn14PS IgG antibodies on Day 7.

Codelivery of adjuvants at the primary immunization site is essential for evoking a robust immune response to neoglycoconjugates.

A series of nonformulated adjuvants, i.e. Quil-A, MPL, DDA, CpG and Alum were codelivered with a synthetic branched tetrasaccharide fragment corresponding to Streptococcus pneumoniae type 14 polysaccharide (Pn14PS) conjugated to CRM(197) in order to investigate antibody- and cell-mediated immune responses in a mouse model.