A therapeutic composition comprising (a) a yeast vehicle and (b) an HCV fusion protein that is recombinantly expressed by the yeast vehicle, the HCV fusion protein comprising a truncated HCV E1 protein fused to a truncated HCV E2 protein, an isolated fusion protein comprising an amino acid sequence of SEQ ID NO:6, an isolated nucleic acid molecule comprising a nucleic acid sequence encoding the fusion protein and a recombinant nucleic acid molecule comprising the isolated nucleic acid molecule.