On the use of adenovirus dodecahedron as a carrier for glycoconjugate vaccines.

Virus-Like Particles (VLPs) have been used as immunogenic molecules in numerous recombinant vaccines. VLPs can also serve as vaccine platform to exogenous antigens, usually peptides incorporated within the protein sequences which compose the VLPs or conjugated to them. We herein described the conjugation of a synthetic tetrasaccharide mimicking the Streptococcus pneumoniae serotype 14 capsular polysaccharide to recombinant adenoviral type 3 dodecahedron, formed by the self-assembling of twelve penton bases and investigated the induced immune response when administered subcutaneously (s.c.). Whether formulated in the form of a dodecahedron or disassembled, the glycoconjugate induced an anti-protein response after two and three immunizations equivalent to that observed when the native dodecahedron was administered. On the other hand, the glycoconjugate induced a weak anti-IgM response which diminishes after two doses but no IgM-to-IgG switch was observed in mice against the serotype 14 capsular polysaccharide. In definitive, the whole conjugation process preserved both particulate nature and immunogenicity of the adenoviral dodecahedron. Further studies are needed to fully exploit adenoviral dodecahedron potential in terms of plasticity towards sequence engineering and of its capacity to stimulate the immune system via the intranasal route of administration as well as to shift the response to the carbohydrate antigen by playing both with the carbohydrate to protein ratio and the length of the synthetic carbohydrate antigen.