Human monoclonal antibody against Hepatitis B virus surface antigen (HBsAg)

Hepatitis B virus (HBV) is one of the main pathogens responsible for hepatitis and hepatocellular carcinoma. Human plasma-derived Hepatitis B immune globulin (HBIG) is being used for prophylactic and liver transplantation currently. However, it may be necessary to replace a HBIG with a recombinant one because of limited availability of human plasma with high anti-HBsAg antibody titer and possible contamination of human pathogens. A Chinese hamster ovary (CHO) cell line, HB-C7A, was established which produces a fully human IgG1 that binds HBsAg. The HB-C7A exhibits ∼2600 units/mg of antibody. The affinity (Ka) of HB-C7A is 1.1 × 108 M−1 by Biacore analysis and estimated 6.7-fold higher than that of Hepabig® (a plasma-derived HBIG from Green Cross Corp., Yongin, Korea) by competition ELISA. The HB-C7A recognizes the conformational “a” determinant of HBsAg and binds HBV particle more efficiently than the Hepabig®. The HB-C7A binds to HBV-infected human liver tissue but does not bind to normal human tissues. This HB-C7A has several advantages compared to plasma-derived Hepabig® such as activity, safety and availability.