胰腺癌荷瘤鼠吲哚胺2,3-双加氧酶表达和CD4~+CD25~+Treg细胞数的变化

目的 观察吲哚胺2,3-双加氧酶(IDO)的表达以及调节性T细胞(Treg)数量在胰腺癌荷瘤鼠中的变化,并探讨胰腺肿瘤细胞免疫逃逸的机制.方法 建立小鼠胰腺癌模型,荧光定量聚合酶链反应(PCR)、Western blot分析肿瘤组织周嗣引流淋巴结(TDLNs)IDO表达水平;并利用流式细胞术检测荷瘤鼠TDLNs及脾脏中CD4~+CD25~+T细胞占CD4~+T比例;荧光定虽PCR测量Foxp3在TDLNs及脾脏mRNA水平.结果 胰腺癌荷瘤鼠TDLNs中IDO在mRNA(1.670±0.099比1.123±0.243),蛋白表达水平(1.401±0.079比0.872±0.193),高于正常对照组.差异均有统计学意义(P<0.05);荷瘤鼠和脾细胞中CD4~+CD25~+T细胞占CD4~+T细胞的比例明显高于对照鼠[TDLNs分别为(25.00±2.16)%和(11.02±1.31)%,P<0.05;脾脏分别为(22.14±2.33)%和(12.11±0.93)%,P<0.05];荷瘤鼠Foxp3 mRNA表达水平显著高于对照鼠,荷瘤鼠分别为:TDLNs 3.427±0.164、脾细胞2.098±0.112,而对照鼠分为:0.933±0.253、1.137±0.343(P<0.05).结论 胰腺癌荷瘤鼠癌组织周围引流淋巴结IDO表达明显增高,且TDLNs及脾脏CD4~+CD25~+Treg细胞的数量增加.

Expression of indoleamine 2,3-dioxygenase and increased prevalence of regulatory T cells in pancreas adenocarcinoma-bearing mice

Objective To investigate the expression of indoleamine 2,3-dioxygenase (IDO) and the prevalence of regulatory T cells (Treg) in tumor draining lymph nodes (TDLNs) and the spleen in a murine pancreas adenocarcinoma model, and study the mechanism by which tumors escaped from immune recognition. Methods Pan02 cell line was injected into syngeneic C57BL/6 mice (n=24) and the IDO expression level in the TDLNs was detected by fluorescence quantitative RT-PCR and Western blot. The prevalence of Treg in the TDLNs and tumor spleen (TS) was assayed by using flow cytometry. The expres-sion level of Foxp3 mRNA was measured in the spleen and TDLNs. Results The expression levels of IDO mRNA and protein in tumor-bering mice (1.670±0.099 and 1. 401±0.079) were significantly higher than in controls (1.123±0. 243 and 0. 872±0.193). The percentage of CD25~+CD4~+T lymphocytes reached (25.00±2.16)% of CD4~+T cells in TDLNs and (22.14±2.33)% in TS. In contrast,the per-eentage of CD25~+ CD4~+ T cells in the lymphocyte nodes (LN) of non-tumor-bearing mice remained (11.02±1.31) % and (12.11±0.93) % respectively. Foxp3 expression was considerably higher in TDLNs and TS than in control LN and spleen. Conclusion The up-regulation of the IDO expression in TDLNs and increased prevalence of Treg in TDLNs and TS are induced by pancreas adenocarcinoma.