ABSTRACT
BACKGROUND: Intracellular antibody specific to hepatitis B virus X protein (HBx) might be useful for studying the role of HBx in hepatocellular carcinogenesis and HBV replication. METHODS: With variable region genes for H7 monoclonal anti-HBx Ab, we constructed a vector for bacterial expression of single chain Ab (scFv) and a vector for eukaryotic cell expression of it. The expression of H7 scFv and its binding activity against HBx was examined by immunoblotting and immunofluorescence microscopy. RESULTS: H7 scFv expressed in bacterial cells retained reactivity to HBx. We demonstrated its intracytoplasmic expression in CosM6 eukaryotic cells. CONCLUSION: This is the first study showing the expression of intracellular anti-HBx Ab in eukaryotic cells. H7 scFv may be a good tool to study the function of HBx in HBV infection