[Inhibitory effect of toll-like receptor 7 agonist on K562 cells]

The aim of this study was to investigate the inhibitory effect of Toll-like receptor 7 (TLR7) agonist gardiquimod on K562 cells. Human γδT cells from peripheral blood cells were amplified by isopentenyl pyrophosphate. The proliferation capacity of γδT cells and K562 cells were measured with MTT assay after treatment with different concentrations of gardiquimod. Cytotoxicity of γδT cells on K562 cells was detected by CCK-8 kit, and the intracellular expression of TLR7, cell cycle and apoptosis of K562 cells before and after treatment with gardiquimod were measured by flow cytometry. The results demonstrated that gardiquimod could significantly stimulate the proliferation of γδT cells, and inhibit proliferation of K562 cells under the concentration of 11.0 µg/ml for 48 h. The expression of TLR7 increased after treatment with gardiquimod. No apoptosis was observed, but there were significant changes in cell cycle, moreover the K562 cells treated with gardiquimod were more killed by γδT cells. It is concluded that the gardiquimod can inhibit the proliferation of K562 cells and enhance their sensitivity to killing activity of human γδT cells.