Properties of a human monoclonal antibody specific for the NS4 region of hepatitis C virus

A human monoclonal IgG1 (kappa) antibody (hmAb) specific for a sequental epitope comprised within the 5-1-1 fragment of the NS4 region of hepatitis C virus (HCV) has been recently generated (1). In this study, B-cell clone supernatant containing the hmAb was purified by passage over a protein A affinity column. Preincubation with synthetic oligopeptides containing the epitope recognized by the hmAb resulted in complete inhibition of binding to the Whole recombinant protein, attesting to its pecificity. Calculation of the dissociation constant (Kd) using a synthetic 20-mer as antigen gave a vallue of 3.3372 x 10(-8) M, consistent with that of a human IgG. We predict that this hmAb will be helpful in characterizing the as yet unidentified native NS4 protein of HCV.