Objective   To construct a recombinant adenovirus encoding β-galactosidase gene (β-gal)

which may be used to treat the lactose intolerance caused by lactase deficiency

with modified AdEasy system.    Methods   The sequence fragment of β-gal was cloned into the shuttle plasmid pAdTrack-CMV

and the homo-logous recombination was completated with backbone plasmid pAdEasy1 in the

E.coli

BJ5183 to construct the recombinant adenoviral plasmid. The adenoviruses were packaged and amplified in the HEK293 cells mediated by liposome. The viral titre was measured by limit

ing dilution assay and the transfection efficiency was observed by X-gal histochemical staining.    Results   The recombinant adenovirus with β-gal was constructed successfully and the viral titre was (2.5~4.0)×10

11

EFU/ml. More than 70% HEK293 cells were transfected when the MOI was 10. Moreover

more than 65% cells were blue after X-gal histochemical staining.    Conclusion   Recombinant adenovirus carrying β-gal with high titre and efficient transfection is constructed successfully by AdEasy system

which supplies valuable experimental basis for the gene therapy to the lactose intolerance caused by lactase deficiency.