Replicating Vesicular Stomatitis Virus Vectors ( VSV ) Expressing Membrane - Anchored MPER Immunogens

lactide)-b-poly (N-vinylpyrrolidone-co-N-acryloxysuccinimide) (PLA-b-P (NVP-co-NAS), 19000–22000 g.mol 1, PDI= 1.5) were prepared by nanoprecipitation and characterized in terms of size (DLS) and critical micellar concentration (cmc). Imiquimod was incubated with the aqueous micellar solution for 1 hour and imiquimod loading in the micelles was quantified by fluorimetry. The micelles were further surface functionalized p24 antigen, through amine reaction with the N-succinimidyl esters of the NAS units at micelle surface in PBS pH 7.4 for 20 hours. Protein coupling on the micelles were investigated by SDS-PAGE. The expression of DC maturation/activation markers CD80, CD83, CD86 induced by the micelles was assessed in vitro by flow cytometry. Results: The micelles initially prepared from the PLA-b-P(NVPco-NAS) copolymer exhibited a mean diameter of 58 nm and a CMC of 20mg.mL 1 . Hydrophobic imiquimod was encapsulated at a loading of 1.5% (w/w). The imiquimod-loaded micelles were further highly surface-functionalized with p24 antigen, at a level of 0.12mg p24 per mg of micelle, with a final size of 110 nm. Imiquimod encapsulated in the micelles was shown to induce up-regulation of the DC maturation markers. Conclusion: Such novel micelle-based systems could thus be promising for vaccine delivery, particularly considering their ability to potentially reach DCs in the lymph nodes, due to their small size ( < 120 nm).