Recombinant Anti-pre S2 protein x Anti-S protein Bispecific Antibody (Tandem Fab) is designed to be expressed as three chains derived from the variable domains of anti-pre S2 protein and anti-S protein parental antibodies. It contains a His-tag for affinity purification. And the two Fd regions are connected by a flexible linker. This BsAb can bind two antigens simultaneously. It is designed for the research of HBV infection therapy.