Recombinant Anti-CD3 x Anti-CD4 Bispecific Antibody (Tandem Fab) is designed to be expressed as three chains derived from the variable domains of anti-CD3 and anti-CD4 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 T cells to HIV-1 infected cells. It is designed for the research of HIV-1 infection, AIDS therapy.