Antigen binding and stability properties of non-covalently linked anti-CD22 single-chain Fv dimers

By varying linker length and domain orientation three multivalent derivatives of a monovalent anti-CD22 single-chain fragment variable (scFv) antibody were generated. Shortening the linker of the V-H-V-L oriented scFv to 5 or 0 residues resulted in the formation of diabodies or a mixture of tetramers and trimers, respectively. Unexpectedly, a V-L-0-V-H scFv assembled to homogenous dimers, remained substantially more stable than the V-H-5-V-L diabody when incubated in human serum at 37 degreesC, and retained its dimeric state when concentrated up to 4 mg/ml. These properties suggest the V-L-0-V-H scFv could become an attractive vehicle for the selective delivery of multiple effector molecules to CD22(+) tumor cells. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.