C11D5.3 is an IgG1 mouse monoclonal antibody specific for BCMA, which is a target for the immunotherapy of multiple myeloma and lymphomas. C11D5.3 scFv is the most commonly used ectodomain componse of BCMA-specific CARs. So far, multiple reported CART BCMA trials contain the anti-BCMA scFv derived from C11D5.3, such as FDA approved CARs Abecma.