Hepatitis B virus (HBV) expresses three types of surface antigens, i.e. S-, M-, and L-protein. L-protein is composed of S-, Pre-S2, and Pre-S1 region. The deletion of Pre-S1 region Forms M-protein and further deletion of Pre-S2 region results in S-protein. Most of commercially available HBsAg is composed of either S-protein alone or a mixture of S- and M-proteins. HBV-infected patients generally possess antibody against S-protein, since most circulating antigen is S-protein. HBsAgL-protein-ST type contains all the three components in one protein. The S-protein region, however, is so modified that the regular human antibody to S-protein does not recognize. The Pre-S1 and Pre-S2 region is intact and shows high antigen activity.The Pre-S1 region is known to be the hepatic cell recognition site and to be important in the HBV infection. And Pre-S2 region is also known to play important role in HBV infection. Thus, the product can be used as a unique tool to investigate themechanism of HBV infection as well as antigens for both Pre-S1 and Pre-S2. The product is also used as an antibody-escapable mimic antigen.
