[Cloning and expressing of an anti-CD5 single chain antibody]

Novel anti-CD5 single-chain fragment of variable domain (ScFv) was cloned and expressed. Anti-CD5 ScFv was constructed with cDNA fragments of heavy and light variable regions (VH and VL) which were reverse-translated from poly (A) mRNA of hybridoma cells producing anti-CD5 McAb. By phage displaying, ScFv in form of ScFv-g3p fusion protein was panned based on its binding capacity to the CD5 antigens on the cell surface of Molt-4 cells. Assayed by the cell-ELISA, 4 clones were found to have high affinity to CD5 antigen. DNA sequencing confirmed that the VH fragment is 339 base pairs, the VL 300 bp, and the ScFv belongs to the mice gene family. In E. coli HB2151 the soluble ScFv-CD5 was expressed mainly in the periplasm.