Recombinant Anti-CD89 x Anti-S. pneumoniae Bispecific Antibody (scFv4-Ig) is an appended IgG format, which includes four scFv moieties at the N-termini of the constant regions. It is a bivalent homodimer, in which one anti-CD89 scFv is fused to the CH1 domain of a heavy chain and another anti-S. pneumoniae scFv to the CL domain of a light chain, or vice versa. The resulting leads to 2+2 antigen-binding valency. This BsAb can retarget NK cells to genus plasmodium. It is designed for the research of S. pneumoniae infection therapy.