Methods The CHO/dhfr- cells were transfected with linearized plasmids of pMM-CTLA-4-IgG4/WG and pMMGR. The clones of CHO/pCTLA-4+/pMMGR+ were in suspension cultured in serum-free culture media.

• 方法将线性化的pMM-CTLA-4-IgG4/WG和pMMGR转染CHO/DG44细胞,对阳性克隆进行无血清悬浮培养,Western blot检测细胞培养液中CTLA-4/Ig融合蛋白的表达,筛选出高效稳定表达CTLA-4/Ig融合蛋白的CHO细胞;