An effective immune response against HCV requires the early development of multi-specific class 1 CD8+ and class II CD4+ T cell together with broad neutralizing antibody (NAb) responses. We have produced mammalian cell-derived HCV VLPs incorporating core, E1 and E2 of HCV genotype 1a to produce such immune responses. Here we decribe the biochemical and morphological characterisation of the HCV VLPs and study HCV core specific T cell responses to the particles. The E1 and E2 glycoproteins in HCV VLPs formed non-covalent heterodimers and together with core protein assembled into VLPs with a buoyant density of 1.22 to 1.28 g/cm3. The HCV VLPs could be immunoprecipited with anti-ApoE and anti-ApoC. On electron microscopy the VLPs had a heterogeneous morphology and ranged in size from 40 to 80nm. The HCV VLPs demonstrated dose-dependent binding to murine-derived dendritic cells and the entry of HCV VLPs into Huh7 cells was blocked by anti-CD81 antibody. Vaccination of BALB/c mice with HCV VLPs purified from iodixanol gradients resulted in the production of neutralising antibody responses while vaccination of humanized MHC class I transgenic mice resulted in the prodution of HCV core specific CD8+ T cell responses. Furthermore, IgG purified from the sera of patients chronically infected with HCV genotypes 1a and 3a blocked the binding and entry of the HCV VLPs into Huh7 cells. These results show that our mammalian cell-derived-HCV VLPs induce humoral and HCV specific CD8+ T cell responses and will have important implications for the development of a preventative vaccine for HCV.
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