Selected BsAb formats. BsAbs can be broadly divided into molecules that contain or do not contain an immunoglobulin G backbone with a functional Fc domain. BsABs can be created by chemical crosslinking 2 mAbs or recombinant DNA technology. Fab, fragment antigen binding; CH, heavy chain; CL, light chain; DART, dual-affinity retargeting; sc, single chain; scFv, single-chain variable fragment.