Recombinant Anti-pre S2 protein x Anti-S protein Bispecific Antibody (scDiabody-CH3) is a fusion protein of two scDiabodies connected together by a CH3 region. In single-chain Diabodies, an additional connecting linker is introduced between chains of the anti-pre S2 protein/anti-S protein diabody. The scDiabody with two specificities is fused to each of the CH3 chains to extend half-life. This BsAb can bind two antigens simultaneously. It is designed for the research of HBV infection therapy.