HUMAN RECOMBINANT ANTIBODIES SPECIFIC FOR HEPATITIS-C VIRUS CORE AND ENVELOPE E2 PEPTIDES FROM AN IMMUNE PHAGE DISPLAY LIBRARY

Hepatitis C virus (HCV) is the aetiological agent responsible for most cases of non-A non-B hepatitis. Hepatitis C is a disease of clinical importance because of its high infection rate in blood donors and its persistence as chronic infections which may lead to cirrhosis and hepa tocellular carcinoma in the long term. The variability of the HCV geno me has posed difficulties in serological detection and vaccine design. The recent advance in phage technology offers a means of cloning huma n anti-HCV antibodies of a defined specificity that may have potential therapeutic use. We now report the generation of a phage display libr ary using the V-H genes of a HCV-infected patient and the V-L genes of two non-immune individuals. From this library we were able to obtain specific IgG single-chain Fvs (scFvs) that recognize viral core and en velope proteins by selection on synthetic peptides derived from the co re sequence PKARRPEGRTWAQPG and the envelope E2 sequence RPIDDFDQGWGPI TY. The specificity of the scFvs was demonstrated by their specific re actions with homologous peptides in ELISA and the specific blocking of scFv binding by homologous peptides, in a dose-dependent manner, in i nhibition ELISA. The binding of the anti-core 4c2 to homologous peptid e was blocked by HCV-positive human sera in an antibody-concentration- dependent manner, suggesting that the scFv recognizes a similar if not identical epitope to those of one or more of the polyclonal antibodie s present in the sera.