Expression of recombinant Lym-1 single-chain Fv in Escherichia coli

Lym-1 single-chain Fv (sFv) can be used for targeted radiodiagnosis and therapy of B-lymphocytic malignancies. Lym-1 sFv was constructed and expressed as a glutathione S-transferase fusion protein, using a (G4S)3 linker connecting the C-terminus of the VH domain and the N-terminus of the VL domain of Lym-1. Six histidine residues and an E Tag epitope were introduced at the C-terminus of the sFv. Lym-1 sFv was purified with glutathione-Sepharose 4B affinity chromatography followed by digestion with thrombin. Lym-1 sFv of 28 kDa was confirmed by Western blotting with anti-(E Tag) monoclonal antibody. An antigen binding assay of Lym-1 and a CD study indicated that it is functionally active.