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CTLA4Ig是人CTLA4胞外区与人免疫球蛋白铰链区、CH2区、CH3区组成的融合蛋白,可以与B7结合,通过阻断B7与CD28的结合,从而阻断B7介导的T细胞活化必需的共刺激信号,可作为免疫抑制剂用于器官移植。将CTLA4Ig融合分子克隆到真核表达载体pCI-dhfr,并用脂质体方法转染到COS7和CHO-dhfr-细胞中,用氨甲喋呤筛选转染的CHO-dhfr-细胞。用RT-PCR、ELISA、细胞免疫荧光染色和Western-blot鉴定重组蛋白的表达。采用A蛋白纯化重组蛋白。
CTLA4Ig is a fusion protein consisting of human CTLA4 extracellular domain and human immunoglobulin hinge region, CH2 region and CH3 region. It can bind to B7 and block B7-mediated T cell activation by blocking the binding of B7 to CD28 Of costimulatory signals, can be used as an immunosuppressive agent for organ transplantation. The CTLA4Ig fusion molecule was cloned into the eukaryotic expression vector pCI-dhfr and transfected into COS7 and CHO-dhfr- cells by lipofectamine. The transfected CHO-dhfr- cells were screened with methotrexate. The expression of the recombinant protein was identified by RT-PCR, ELISA, immunofluorescence staining and Western-blot. Protein A is used to purify the recombinant protein.