Human antibodies from phage display libraries: expression of recombinant full length immunoglobulin G specific to the Hepatitis C virus E2 glycoprotein

Evidence from clinical and experimental studies indicates that hepatitis C virus E2 glycoprotein (HCV/IE2) represents a major target antigen involved in the containment and resolution of naturally occurring HCV infection. Antibody phage display allows the molecular cloning of cDNA sequences encoding antibody fragments specific to a wide range of diverse antigens. These antibodies may be produced in bacteria as Fab or converted into full length IgG. The latter have a higher serum half life and display Fc encoded function. Using a library prepared from an HCV-infected individual, we selected a panel of Fab fragments for binding to invariant epitopes of the E2 glycoprotein. This work describes a technique used to convert the selected Fab fragments into full length IgG and to express these antibodies in eukaryotic cells. All the recombinant antibodies retained the binding specificity of the parental Fab showing an increase in apparent relative affinity for E2.