Recombinant Anti-CD7 x Anti-saporin Bispecific Antibody (scFv4-Ig) is an appended IgG format, which includes four scFv moieties at the N-termini of the constant regions. It is a bivalent homodimer, in which one anti-CD7 scFv is fused to the CH1 domain of a heavy chain and another anti-saporin scFv to the CL domain of a light chain, or vice versa. The resulting leads to 2+2 antigen-binding valency. This BsAb can be used in pretargeting system and deliver immunotoxin to tumor cells. It is designed for the research of Multiple myeloma (MM); Hematologic malignancies therapy.