Construction of antigenized antibodies expressing an immunodominant epitope AA32-45 of the hepatitis C virus core protein

By using site-directed mutagenesis, we created a unique Xho I site in the CDR3 of the heavy-chain variable domain(V-H). Two antibody molecules, one carrying one or and the other two repeats of an immunodominant epitope AA32-45 (GVYLLPRRGPRLGV) of the hepatitis C virus core protein in CDR3 of V-H were engineered and designated Ig-E1, Ig-E2 respectively. We showed that both antigenized antibodies lost the HBsAg-binding ability and the insertion of one repeat of GVYLLPRRGPRLGV epitope into the CDR3 of the V-H domain did not appreciably affect the H chain to assemble with L chain to form a stable H2L2 tetramer. Ig-E1 was able to be recognized by the polyclonal antibody against AA1-58 of the core protein as characterized by Western blot. However, Ig-E2 could not be assembled into H2L2 tetramer.