Characterization of human monoclonal antibodies directed against hepatitis B surface antigen

Four hybridoma cell lines stably secreting human monoclonal antibodies directed against hepatitis B surface antigen have been isolated. The monoclonal antibodies have been characterized by determining several allotypes, measuring affinity for HBsAg, binding to two HBsAg subtypes, and kinetics of antibody binding to solid adsorbed antigen. In addition, the relative position of the epitopes have been determined by competition in binding to HBsAg. The results indicate that human anti-HBsAg monoclonal antibodies of quite different properties can be isolated. Pharmacokinetics of one antibody have been measured in two rhesus monkeys. This monoclonal antibody, OST 577, has been compared to hyperimmune gamma globulins in a Bureau of Biologics approved radioimmunoassay. It is expected that these antibodies will be useful in preventing and treating hepatitis B.