Recombinant Anti-pre S2 protein x Anti-S protein Bispecific Antibody (Tandem scFv) is designed to be expressed as a scFv from an anti-pre S2 protein antibody variable domains fused with a scFv from an anti-S protein antibody variable domains. It contains a His-tag at the C/N terminus for affinity purification. The BsAb exits as monomer in reducing and non-reducing conditions. This BsAb can bind two antigens simultaneously. It is designed for the research of HBV infection therapy.