Recombinant Anti-albumin x Anti-IL-6R Bispecific Antibody (Tandem scFv-Fc) is designed to be expressed as a homodimer, which has 2+2 antigen-binding valency. This format consists of one Fc region and two tandem scFv fragments, in which the anti-albumin/IL-6R tandem scFv is fused to the Fc domain. The engineered fragment format is used to extend the half-life. This BsAb can act as PK-modulated receptor antagonist. It is designed for the research of Lupus, rheumatoid arthritis therapy.