Abstract: To investigate the antitumor activity of NK92 cells induced by interleukin18(IL18) combined with interleukin2(IL2). Methods: NK92 cells were induced by IL18 at different doses in combination with IL2 (5?U/ml) in vitro, and then flowcytometry was used to observe the changes of cell cycle, LDH releasing test to examine NK92 cells and its supernatant mediated cytotoxic activity on the growth of ovarian carcinoma cell line in vitro, and enzymelinked immunosorbent assay (ELISA) to qualify the IFNγ and TNFα levels in supernatant when NK92 cells exhibited the highest cytotoxicity. Results: There was a statistical uptendency in S phase proportion of NK92 cells after stimulated by IL18(25?ng/ml) and IL2(5?U/ml), whereas a statistical downtendency in G0/G1 phase proportions among normal control(P＜0.05). When the effectortotarget ratio was 10:1, the NK92 cells exhibited the highest cytotoxicity on SKOV3 cells 4 hours later. Before and after being stimulated with IL18 and IL2, the cytotoxicity of NK92 cells was (42.3±4.82) % and (77.63±5.27)% respectively. After incubated with target cells for 36 hours，NK92 supernatant exhibited the highest cytotoxicity on SKOV3 cell, and before and after stimulation, the cytotoxicity of NK92 supernatant was (21.2±3.49)% and (37.14±2.69) % respectively. The levels of IFNγ and TNFα in the supernatant were elevated significantly when NK92 cells exhibited the highest cytotoxicity on SKOV3 cells (P＜0.05). Conclusion: IL18 in combination with IL2 may increase the antitumor activity of NK92, which provides the experimental basis for immunotherapy of ovarian tumor with NK92 cells.

Key words: Killer cells, natural, Ovarian tumor, Interleukin 18, Interleukin 2, Immunotherapy, adoptive