Expression of adenovirus-mediated CTLA4Ig-IRES-CTLA4 gene in bone marrow mesenchymal stem cells / 解放军医学杂志

ABSTRACT

Objective To construct adenovirus vector harboring CTLA4Ig-IRES-CTLA4 gene, and to express the gene in bone marrow mesenchymal stem cells (BMMSCs). Methods The cDNA fragments of CTLA4, and the extracellular domains of CTLA4 and IgGFc were cloned to pT-Easy vectors by RT-PCR from the activated splenocytes of Wistar rats. Recombinant adenovirus vector harboring CTLA4Ig-IRES-CTLA4 was produced from AdeasyTM Adenoviral Vector System by homologous recombination between the Adtrack vector (pAdtrack-GFP-CTLA4Ig-IRES-CTLA4) and the plasmid pAdEasy-1 containing most of the human adenovirus serotype 5 (Ad5) genome in E. coli BJ5183 strain, and then packaged and propagated in 293 cells. BMMSCs were infected with the recombinant adenovirus, and the co-expression of both CTLA4Ig and CTLA4 was then detected by RT-PCR and Western blotting. The immunosuppression function of the transfected BMMSCs was investigated by mixed lymphocyte response (MLR). Results Fusion gene CTLA4Ig was constructed successfully, and the recombinant CTLA4Ig-IRES-CTLA4 adenovirus was then generated by homologous recombination and packaged in 293 cells. The transduction efficiency of recombinant adenovirus in BMMSCs was elevated up to 98.67% determined by flow cytometry using a GFP as marker. CTLA4Ig and CTLA4 were expressed at the same time in BMMSCs detected by RT-PCR and Western blot, and the transfected stem cells showed stronger immunosuppression function than that of BMMSCs or BMMSCs transduced by Ad-CTLA4Ig. Conclusion The BMMSCs transfected by the recombinant adenovirus can co-express CTLA4Ig and CTLA4, which improved the immunosuppression function of BMMSCs in the way of costimulatory pathway blockade.