DISSECTION OF HUMAN HUMORAL IMMUNE-RESPONSE AGAINST HEPATITIS-C VIRUSE2 GLYCOPROTEIN BY REPERTOIRE CLONING AND GENERATION OF RECOMBINANT FAB FRAGMENTS

Demonstration of antibodies inhibiting key viral functions is the basi s for the design of an effective vaccine. Dissection of the human anti body response by repertoire cloning may be a powerful means to address this issue. In this study, a panel of human monoclonal recombinant Fa b fragments specific for hepatitis C virus (HCV) E2 envelope protein w as generated. The selection procedure was designed to select for cross -genotype reactive antibodies. Sequences coding five different human r ecombinant Fabs specific for the HCV/E2 protein were cloned and charac terized. The ability of the cloned antibody fragments to inhibit adhes ion of recombinant envelope E2 protein to target cells was assayed. Wh ile affinity of the different antibody fragments appeared similar, act ivity in inhibiting E2 binding to target cells varied considerably fro m one Fab fragment to another. Two Fabs were not able to inhibit E2 bi nding at high concentration (40 mu g/mL), while three other Fab clones were active in neutralizing 50% of the E2 binding at concentrations r anging from 3 to 0.35 mu g/mL.