摘要AIM To construct an expression vector for anti-HBsAg antibody Fab fragment and interferon-aA (IFN-aA)fusion protein in E. coli.METHODS With PCR and molecular clone techniques, we amplified the gene fragment of IFN-aA withcorresponding endonuclease sites and artificial linker at 5', 3' termini, and then formed pHS/IFN-aA byrecombining it within the vector in correct endonuclease sites, choosing the positive clone to transform intoE. coli and intoduced by IPTG to express the fusion protein.RESULTS Enzymic hydrolysis and DNA sequence measurement confirmed that human gene of IFN-aA wascorrectly cloned to the vector and could express fusion protein in E. coli.CONCLUSION The success in construction and expression of a fusion protein makes it possible to carry outfurther studies on its purification and targeted polypeptide therapy to HB virus.