Recombinant Anti-CD89 x Anti-S. pneumoniae Bispecific Antibody (Tandem Fab) is designed to be expressed as three chains derived from the variable domains of anti-CD89 and anti-S. pneumoniae parental antibodies. It contains a His-tag for affinity purification. And the two Fd regions are connected by a flexible linker. This BsAb can retarget NK cells to genus plasmodium. It is designed for the research of S. pneumoniae infection therapy.