Recombinant Anti-CD89 x Anti-S. pneumoniae Bispecific Antibody (Tandem scFv-Fc) is designed to be expressed as a homodimer, which has 2+2 antigen-binding valency. This format consists of one Fc region and two tandem scFv fragments, in which the anti-CD89/S. pneumoniae tandem scFv is fused to the Fc domain. The engineered fragment format is used to extend the half-life. This BsAb can retarget NK cells to genus plasmodium. It is designed for the research of S. pneumoniae infection therapy.