BACKGROUND: A single-chain antibody (ScFv) phage display library was created by cloning antigen-binding regions of VH (variable domain) and VL gene repertoires as fusion proteins with a minor coat protein of filamentous phage, from which high affinity completely humanized ScFv against PreS1 of hepatitis B virus could be screened and characterized.
METHODS: A combinatorial library of phage-display human ScFv genes, which were derived from peripheral blood lymphocytes immunized by peptide PreS1 in vitro, was constructed. The library contained 7×108 clones.
RESULTS: After 3 rounds panning, a high affinity (K=10-7-10-8 mol/L) ScFv specific to PreS1 was obtained. Sequence analysis showed that the VH belonged to the VH4 family and Vλ to Vλ4.
CONCLUSIONS: The described ScFv may provide a more satisfactory therapy. This application further illustrates that the method of in vitro antigen stimulation is expeditious for the source of human immune antibody library.