Objective　To observe the expression of CTLA4Ig in normal human liver cell line L02 that transducted with Ad-CTLA4Ig-EGFP

and to explore their biological activity and changes in biological characteristics. 　Methods　Normal liver cells L02 were transducted with Ad-CTLA4Ig-EGFP. The expression of green fluorescence in the cells was observed. Immunocytochemistry

Western blotting and ELISA were used to detect the expression of CTLA4Ig in L02 cells. Changes of biological characteristics in CTLA4Ig transducted L02 cells (CTLA4-L02) were observed through cell proliferation curve and urea synthesis. After the transducted cells were co-cultured with rat splenocytes for 72 h

the proliferation of splenocytes were detected by MTT assay. The co-cultured splenocytes were then co-cultured with HeLa cells and normal L02 cells respectively for another 72 h

then the proliferation of splenocytes was examined again. 　Results　CTLA4Ig were highly expressed in the cytoplasm of CTLA4-L02 cells

and were secreted to the culture supernatant. No obvious change in growth speed was observed after transduction (P0.05)

but the synthesis of urea was enhanced after transduction [(0.56±0.01) pmol/d

P0.01]. The proliferation of rat splenocytes was inhibited by 36.8% (P0.05) when co-cultured with CTLA4-L02. The inhibited splenocytes mentioned previously kept a low proliferative rate when co-cultured with normal L02 cells

but showed a high proliferative rate when co-cultured with HeLa cells (P0.01).   Conclusion　After transfected with Ad-CTLA4Ig-EGFP

L02 cells express active CTLA4Ig and  show immunological inhibition

but no obvious negative change in biological characteristics is observed.