A modified hepatitis C virus E2 glycoprotein, which comprises the HCV-E2 receptor-binding domain, wherein the modification consists of: (a) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; (b) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR1 variable region, as defined by amino acid residues 384 to 410 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence; (c) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR2 variable region, as defined by amino acid residues that occur between Cys459 and Cys486 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence; or (d) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR1 variable region, as defined by amino acid residues 384 to 410 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR2 variable region, as defined by amino acid residues that occur between Cys459 and Cys486 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence; wherein the modified HCV E2 glycoprotein elicits antibodies directed to the conserved core region that neutralise HCV; and further wherein the glycoprotein binds to the HCV receptor CD81. (a) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; (b) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR1 variable region, as defined by amino acid residues 384 to 410 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence; (c) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR2 variable region, as defined by amino acid residues that occur between Cys459 and Cys486 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence; or (d) a deletion in whole or in part of the igVR variable region, as defined by amino acid residues that occur between Cys569 and Cys581 in the full-length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR1 variable region, as defined by amino acid residues 384 to 410 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence; and a deletion in whole or in part of the HVR2 variable region, as defined by amino acid residues that occur between Cys459 and Cys486 in the full length E2 sequence of the prototype HCV-H77 polypeptide sequence;