RESUMO
Objective To investigate the effect of Tiopronin (TIP) on interleukin (IL)-2 immunotherapy of human leukemia KG-1 cells and its possible mechanism.Methods KG-1 ceils in logarithmic growth phase were randomly divided into KG-1 + IL-2 group and KG-1 + IL-2 + TIP group.Methyl thiazolyl tetrazolium (MTI) assay and colony formation assay were used to detect the sensitivity and proliferation of KG-1 cells.The changes of reactive nitric metabolites (RNM) were detected with nitrate reductase method.The production of tumor necrosis factor (TNF)-3 and interferon (IFN)-γ,was detected with enzyme linked immunosorbent assay (ELISA).The expression of CD3ξ was detected with Western blot and real time polymerase chain reaction (RT-PCR).Results IL-2 and IL-2 + TIP could inhibit the growth of KG-1 cells.The inhibitory rate of KG-1 + IL-2 + TIP group was significantly higher than that of KG-1 + IL-2 group,and the sensitivity of KG-1 cells to IL-2 was 6.2 times higher.Both IL-2 and IL-2 + TIP group inhibited the colony formation of KG-1 cells.Compared to KG-1 + IL-2 group,KG-1 + IL-2 + TIP group inhibited the colony formation of KG-1 cells by 3.5 times.The RNM production of KG-1 + IL-2 group was (158.26 ± 3.82) μmol/ml,which was significantly higher than (45.18 ± 4.29) μ mol/ml of KG-1 + IL-2 + TIP group (P ＜ 0.05).The levels of TNF-β and IFN-γin KG-1 + IL-2 + TIP group were (253.28 ± 7.84) pg/ml and (181.25 ±6.41) pg/ml,which was significantly higher than (98.45 ±6.43) pg/ml and (68.74 ±8.26) pg/ml of KG-1 +IL-2 group (P＜0.05).The expression of CD3ξ in KG-1 +IL-2 +TIP group was significantly higher than that in KG-1 + IL-2 group.Conclusions Tiopronin can promote NK/T cell activity and increase the sensitivity of leukemia KG-1 cells to IL-2 by eliminating reactive nitrogen metabolites.