Recombinant Anti-BAFF x Anti-B7RP1 Bispecific Antibody (scFv-CH3) contains two chains. The anti-BAFF scFv is fused to the Knob-CH3 domain via a hinge region and the same as the anti-B7RP1 scFv to the Hole-CH3 domain, or vice versa. The KIH CH3 domains can facilitate to form a heterodimer and this bivalent binding leads to improvement in avidity. This BsAb can bind and inactivate two ligands simultaneously. It can inhibit B cell survival and T cell costimulation. It is designed for the research of Systemic lupus erythematosus (SLE) therapy.