[Expression of truncated fragment of human OPG in CHO-DHFR- cells and its bioactivity characterization].

To obtain high level expression of recombinant human truncated osteoprotegerin (TOPG) with higher bioactivity in CHO-DHFR(-) cells. The recombinant vector pcDNA3.1/DHFR-TOPG was constructed and transfected into CHO-DHFR(-) cells by the directions of LipofectAMINE 2000 for stable expression. The stable expression cell strains were screened by selective medium IMDM with 50 mL/L FCS, then serially passed in methotraxate (MTX) for gene amplification. The expression were analyzed by ELISA and RT-PCR. At last, the bioactivity analysis was performed in vitro. The expression level of recombinant truncated human OPG was up to 6 mg/L x 72 h, and it had significant suppression effect on the formation of OLC (P<0.05). Recombinant truncated human OPG has high expression and bioactivity. The results make it possible for further studying and clinical implying of OPG.