Abstract: The present invention relates generally to an immunogenic complex comprising a charged organic carrier and a charged antigen and, more particularly, a negatively charged organic carrier and a positively charged antigen, wherein the charged antigen is a polyprotein of Hepatitis C Virus (HCV), particularly the core protein of HCV, or a fragment thereof, or a fusion protein comprising the polyprotein or a fragment thereof. The complexes of the present invention are useful, inter alia, in vaccine compositions as therapeutic and/or prophylactic agents for facilitating the induction of immune responses, and in particular a cytotoxic T-lymphocyte response, in the treatment of a disease condition which results from an HCV infection.