Objective    To construct the recombinant adenovirus for nature antibiotic elafin protein and observe its expression in primary airway epithelia.      Methods    The elafin gene was amplified by RT-PCR from lung tissues

then the fragment was inserted into the multiple clone site of pAdTrack-CMV. The linearized shuttle plasmid was homogenously recombined with AdEasy-1 in BJ5183. The candidate clone was further analyzed by restriction endonuclease digestion

PCR

and sequencing. Then the recombinant adenovirus plasmid was digested with PacⅠ and transfected into 293 cells for packaging and amplification. Infection titer and rate were monitored by green fluorescent protein (GFP) expression. Finally the primary airway epithelium was infected with Ad-elafin

and the GFP expression was observed by fluorescence microscope in epithelial cells 24 h after transfection. The elafin protein was detected by ELISA in the supernatant.     Results    Restriction endonuclease and PCR confirmed that elafin gene was cloned into the adenovirus vector successfully. Twenty-four hours after transfection

the GFP expression was seen by fluorescence microscopy. The concentration of elafin protein was (2.2±0.4) ng/ml in supernatant of transfected group

while that of control group was (1.9±0.3) ng/ml

P0.05.     Conclusion    The recombinant adenovirus vector Ad-elafin was constructed successfully  and can be helpful to research the characteristic of elafin.