Effects of humanized interleukin 21 on anti-leukemic activity of cytokine induced killer cells and the mechanism

To explore the effects of humanized interleukin 21 (IL-21) on anti-leukemic activity of cytokine induced killer(CIK) cells derived from peripheral blood(PB) and the mechanism. Mononuclear cells were separated from peripheral blood and cultured with cytokines to induce CIK cells. Proliferation of CIK cells with or without IL-21 stimulation and their cytotoxic activity against K562 cells was measured by MTT method. IL-21 receptor (IL-21R) and immunophenotypes of CIK cells were measured by flow cytometry. The expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), tumor necrosis factor-β (TNF-β), perforin, granzyme A, granzyme B, FasL and NKG2D mRNA were measured by semi-quantitative RT-PCR. FasL on the surface of CIK cells and intra-cellular perforin and granzyme B of CIK cells were measured by flow cytometry. The concentration of IFN-γ and TNF-α in the cultured supernatant were measured by enzyme immunoassay. JAK-STAT signalling pathway of CIK cells were measured by Western-blot. After IL-21 stimu