Recombinant Anti-BAFF x Anti-B7RP1 Bispecific Antibody (scFv-Fc-scFv) is designed to be expressed as one chain, then assembled to a homodimer of bivalent scFv fragments and the Fc region of IgG. The anti-BAFF scFv is fused to the N-terminus of Fc via a hinge region while another anti-B7RP1 scFv is linked to the C-terminus of Fc. This scFv-Fc-scFv format has 2+2 antigen-binding valency by employing different scFv fragments. 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.