Soluble expression and purification of recombinant human interleukin-21 in escherichia coli

Objective To investigate the soluble expression and purification of recombinant human interleukin-21(rhIL-21) in escherichia coli(E.coli),and analyze its immunologic activity in vitro.Methods The E.coli DH5α containing recombinant plasmid pGEX4T-2∕IL-21 was induced to express protein by IPTG.Supernatants of lysate was purified by affinity chromatography,thrombin digestion and cation chromatography sequentially.The purified products were analyzed by SDS-PAGE.The effect of rhIL-21 on proliferation of T lymphocyte was studied by using MTT method.Results The target protein was soluble in the supernatant.Purity of rhIL-21 was 95%.The proliferation of T lymphocyte increased after treated by rhIL-21 in vitro.Conclusion Soluble rhIL-21 can be successfully expressed and purified;rhIL-21 can promote the proliferation of T lymphocyte.