Recombinant Anti-CD22 x Anti-saporin Bispecific Antibody (scDiabody-CH3) is a fusion protein of two scDiabodies connected together by a CH3 region. In single-chain Diabodies, an additional connecting linker is introduced between chains of the anti-CD22/anti-saporin diabody. The scDiabody with two specificities is fused to each of the CH3 chains to extend half-life. This BsAb can be used in pretargeting system and deliver immunotoxin to tumor cells. It is designed for the research of Lymphoma therapy.