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

AbstractBy 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 VH–VL oriented scFv to 5 or 0 residues resulted in the formation of diabodies or a mixture of tetramers and trimers, respectively. Unexpectedly, a VL–0–VH scFv assembled to homogenous dimers, remained substantially more stable than the VH–5–VL diabody when incubated in human serum at 37 °C, and retained its dimeric state when concentrated up to 4 mg/ml. These properties suggest the VL–0–VH scFv could become an attractive vehicle for the selective delivery of multiple effector molecules to CD22+ tumor cells