Check-BODY platform is designed to develop innovative symmetric tetravalency BsAbsBoth Fab and Fv moieties of a Check-BODY antibody show high affinity to the targets. Due to the symmetric structure, the purification process of Check-BODY antibodies is similar to that of IgG-like monoclonal antibodies. Multiple batches Check-BODY antibodies are produced in consistently high quality and could easily scale up the production. YZYBIO has discovered and developed Y101D, a PD-L1 × TGF-β BsAb, based on our Check-BODY platform.