Roger Kravtzoff

Intranasal immunization with recombinant antigens associated with new cationic particles induces strong mucosal as well as systemic antibody and CTL responses

New cationic nanoparticles (SMBV) were evaluated for use as a nasal vaccine delivery system for two recombinant proteins: HBsAg and beta-galactosidase. Each protein was formulated with SMBV and intranasally administrated to non-anesthetized mice. In each model, the formulated protein induced high levels of specific serum IgG antibodies and cytotoxic T lymphocyte (CTL) responses. Moreover, specific IgA antibodies were found in nasal as well as in vaginal washes of intranasally immunized mice with the protein associated with SMBV. In contrast, no IgG or IgA antibodies and no CTL were detected in mice immunized with free protein. The detection of a CTL response and an increase in both IgG1 and IgG2a antibodies in serum suggest that SMBV amplifies both Th1 and Th2 responses without modifying the Th1/Th2 profile of the immune response induced by the natural protein. These data demonstrate the high potential of SMBV for use as a nasal delivery system for sub-unit vaccines.

Proofs of the structure of lipid coated nanoparticles (SMBV) used as drug carriers.

AbstractPurpose. Supramolecular Biovectors (SMBV™) consist of cross-linkedcationic nanoparticles surrounded by a lipid membrane. Thepurpose was to study the structure of the lipid membrane and tocharacterise its interaction with the nanoparticles in order to differentiateSMBV™ from other polymer/lipid associations. Methods. The interaction of lipids with the nanoparticle surface wasstudied using zeta potential, Fluorescence Energy Transfer (FET) andFluorescence Microscopy. SMBV™ were compared to liposomes andmixtures nanoparticles/liposomes. Finally the structure of SMBV™was visualised by Electron Microscopy. Results. Zeta potential measurements showed that lipids on SMBV™had a pronounced shielding effect on the surface charge. This was notthe case for mixtures of nanoparticles and liposomes. FET experimentsconfirmed these results indicating that, for SMBV™, the lipids aremuch closer to the nanoparticle surface. SMBV™ Fluorescence microscopyon model microparticles showed a lipid crown on SMBV™ thatwas confirmed by electron microscopy on SMBV™ nanoparticles. Conclusions. Results show that in case of SMBV™ lipids are stronglyadsorbed on the polysaccharide core surface probably due to ionic/hydrophobicinteractions. The resulting supramolecular structure is aspherical cationic polysaccharide particle surrounded by a phospholipid/cholesterol layer.