目的： 探讨IL-12通过诱导肝癌微环境中NK细胞活化诱导抗肿瘤的效果。 方法： NOD/SCID小鼠皮下注射肝癌HepG2细胞，成瘤后腹腔注射人外周血淋巴细胞（peripheral blood lymphocyte， PBL），建立HCC-huPBL荷瘤小鼠模型。将荷瘤小鼠随机分为IL-12组和PBS对照组，瘤内注射IL-12后，观测荷瘤小鼠瘤体积、体重、一般状况的变化，IL-12瘤内注射后第30天ELISA法检测荷瘤小鼠肝癌组织微环境中IL-12、INF-γ含量以及小鼠外周血中天门冬氨酸氨基转移酶（aspartate aminotransferase，AST）及谷丙转氨酶（alanine aminotransferase，ALT）的含量，免疫组化法检测IL-12治疗后肝癌微环境中NK细胞活化性受体NKG2D、NKp44、NKp30、NKp46，以及抑制性受体KIR2DL3/CD158b、NKG2A/CD159a的表达。 结果： 第12、18、24、30天 IL-12组荷瘤小鼠瘤体积均小于PBS组\[（594.47±205.51） vs （832.10±187.49） mm3，（963.61±427.95） vs （1 350.87±468.23）mm3，（1 285.02±368.56） vs （1 975.49±655.54）mm3，（1 903.64±471.34） vs （2 568.77±784.68）mm3，均P<005\]。 IL-12组小鼠肝癌组织中IL-12与INF-γ的表达水平均明显高于PBS组\[（2.96±1.02） vs （1.35±0.75） pg/ml，（12.26±4.11） vs （7.81±3.46） pg/ml，均P<0.05\]。IL-12组与PBS组相比，血清ALT水平第7天显著升高\[（73.85±1071） vs （41.73±1313）U/L；P<0.05\]，第14天达到高峰。IL-12组治疗后肝癌组织中NK细胞活化性受体NKG2D、NKp44、NKp30的表达较PBS组高（P<0.05），NKp46的表达未见明显升高；而NK细胞抑制性受体CD158b和CD159a表达较PBS组低（P<0.05）。 结论： 肝癌模型小鼠瘤体内IL-12注射可上调瘤组织内NK细胞活化性受体、IL-12、IFN-γ的表达，下调抑制性受体的表达，从而抑制小鼠模型中肿瘤的生长。

Objective:To explore the enhanced anti-tumor effect of IL-12 through inducing NK cell activition in hepatic carcinoma microenviroment. Methods: The hepatic cacinoma HepG2 cells were subcutaneously injected into NOD/SCID mice, and human peripheral blood lymphocytes (PBL) were introperitoneally injected after tumor formation to establish HCC-huPBL tumor-bearing mouse model. The tumor-bearing mice were randomized into IL-12 group and PBS control group. Mice were intratumoral injected with IL-12, and the changes of tumor volume and body weight as well as general conditions of tumor-bearing mice were observed. ELISA assay was performed to examine the expression levels of IL-12 and INF-γ in the microenvironment of hepatic carcinoma tissues in tumor-bearing mice, and the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in peripheral blood of mice 30 days after IL-12 intratumoral injection. Immunohistochemistry assay was used to analyze the expressions of NK-activating receptors: NKG2D, NKp44, NKp30, NKp46, and inhibitory NK receptors: KIR2DL3/CD158b and NKG2A/CD159a in hepatic carcinoma microenvironment after IL-12 treatment. Results: On day 12, 18, 24 and 30, the tumor volumes were smaller in the IL-12 group than those in the PBS group (\[594.47±205.51\] vs \[832.10±187.49\] mm3, \[963.61±427.95\] vs \[1 35087±468.23\] mm3, \[1 285.02±368.56\] vs \[1 975.49±655.54\] mm3, \[1 903.64±471.34\] vs \[2 568.77±784.68\] mm3, P<0.05). The expression levels of IL-12 and IFN-γ in the IL-12 group were significantly higher than those in the PBS group (\[2.96±1.02\] vs \[1.35±0.75\] pg/ml, \[12.26±4.11\] vs \[7.81±3.46\] pg/ml, P<005). The serum ALT level significantly increased in the IL-12 group compared to the PBS group on day 7 (\[7385±10.71\] vs \[41.73±13.13\] U/L, P<0.05), and reached a peak at day 14. The expressions of NK-activating receptors NKG2D, NKp44 and NKp30 were statistically higher in the IL-12 group than those in the PBS group (P<005), the expression level of NKp46 showed no significant up-regulation, while the expression levels of NK inhibitory receptors CD158b and CD159a were decreased compared to the PBS group (P<0.05). Conclusion: IL-12 intratumoral injection can up-regulate the expressions of NK-activating receptors, IL-12 and IFN-γ, and down-regulate the NK inhibitory receptors in the hepatic carcinoma mouse model, therefore effectively inhibiting the tumor growth in mouse model.

福建省卫生厅青年科研基金项目（No. 2009-2-30）；福建省科技厅重点项目（No. 2008I0012）