Recombinant Anti-CD3 x Anti-HIV-1 gp120 Bispecific Antibody (Diabody-Fc) is a fusion protein of two diabodies connected together by an Fc region. In a diabody, the two scFvs with short linkers are from anti-CD3 and anti-HIV-1 gp120 antibodies. The VH and VL domains form an inter-chain pairing. The diabody with different specificities is fused to the Fc fragment, which results in 2+2 antigen-binding valency and exerts Fc-mediated functions or just extends the half-life. This BsAb can retarget T cells to HIV-1 infected cells. It is designed for the research of HIV-1 infection, AIDS therapy.