EB病毒潜伏膜蛋白2A诱导细胞毒性T细胞抗鼻咽癌的体内外实验

目的观察EB病毒（Epstein—Barr virus，EBV）-潜伏膜蛋白2A（1atent membrane protein2A，LMP2A）转染人树突状细胞（dendritic cell，DC）诱导特异性细胞毒性T细胞（cytotoxicity T lymphocyte，CTL）的体外生物学特性；建立表达EBV—LMP2A的裸鼠鼻咽癌动物模型，探讨LMP2A特异性CTL在荷瘤鼠体内的抗肿瘤效应。方法分离人外周血单核细胞（pripheral blood mononuclear cell，PBMC），以粒细胞-巨噬细胞集落刺激因子（granulocyte—monocyte colony stimulating factor，GM—CSF）、白细胞介素4（interleukin-4，IL4）及肿瘤坏死因子（tumor necrosis factor-α，TNF—α）诱导培养获得DC，荧光激活细胞分选仪（fluorescence activated cell sorter，FACS）检测成熟DC的表面分子表达。用LMP2A重组腺病毒转染成熟DC，将转染DC与自体PBMC混合培养，在白细胞介素2（interleukin-2，IL-2）作用下诱导针对LMP2A的特异性CTL，FACS检测CTL群体中阳性细胞的组成。将鼻咽癌CNE细胞接种BALB／c裸鼠，建立鼻咽癌动物模型；在裸鼠肿瘤局部注射LMP2A特异性CTL，观察治疗后移植瘤生长情况及病理变化。结果人外周血PBMC体外在GM—CSF、IL4、TNF—α诱导下获得典型形态及表型特征的成熟DC。FACS检测表明，以LMP2A重组腺病毒转染DC诱导的CTL细胞群体以CIM、CD8阳性细胞组成为主。在接种CNE细胞3周后建立表达EBV—LMP2A的裸鼠鼻咽癌动物模型；动物体内实验表明注射CTL的裸鼠肿瘤生长缓慢，体积明显小于对照组（P〈0．01）；病理检查显示肿瘤局部发生液化性坏死并有淋巴细胞浸润。结论人外周血单核细胞体外经细胞因子诱导，可生成具典型特征的成熟DC。利用LMP2A重组腺病毒将LMP2A基因转入DC，可在同一个体体外诱导出针对LMP2A的特异性CTL。CNE细胞接种裸鼠，可成功构建鼻咽癌动物模型；LMP2A特异性CTL在动物体内可明显抑制鼻咽癌肿瘤的生长，发挥有效的抗肿瘤作用。

Anti-nasopharyngeal carcinoma effect in vivo and in vitro of cytotoxicity T lymphocyte induced by Ad5-latent membrane protein 2A

OBJECTIVE: To study the biological characteristics of cytotoxicity T lymphocyte (CTL) induced by dendritic cell (DC) transfected with the Epstein-Barr virus latent membrane protein 2A (EBV-LMP2A) recombinant adenovirus. To establish nasopharyngeal carcinoma (NPC) animal models expressing LMP2A and investigate the anti-tumor effect of LMP2A specific CTL in vivo. METHODS: The mononuclear cells were isolated from human peripheral blood mononuclear cells (PBMC) and cultured with the cytokines granulocyto-monocyte colony stimulating factor (GM-CSF), interleukin-4 (IL-4) and tumor necrosis factor-alpha TNF-alpha]. The expression of surface markers on mature DC was detected by fluorescence activated cell sorterFACS. Mature DC were transfected with LMP2A recombinant adenovirus. Under the help of interleukin-2 (IL-2), LMP2A specific CTL were induced by coculturing LMP2A-transfected DC with autologous PBMC. The population of CTL was detected by FACS. NPC animal models were constructed by implanting CNE cells expressing LMP2A subcutaneously into BALB/c nude mice. After intra-tumoral injection of LMP2A specific CTL, the size of tumor was measured. The tumors were removed after 30 d and subjected to histological examination. RESULTS: Mature DC displaying typical characteristics of morphology and phenotype were obtained from monocytes cultured in the medium containing GM-CSF, IL-4 and TNF-alpha. The LMP2A specific CTL induced by transfected DC were composed of mainly CD4+ and CD8+ T cells. The NPC animal models were constructed three weeks after implanting CNE cells. The study in vivo indicated that the tumors treated with LMP2A specific CTL grew slowly compared with control. Tumor volume of treated groups was significantly smaller than that of controls. The histological sections showed local necrosis and infiltration of lymphocyte in tumor tissue. CONCLUSIONS: Typically mature DC could be generated in vitro by culturing monocytes with the cytokines. LMP2A-specific CTL could be induced by LMP2A transfected DC in vitro. NPC mice modals could be constructed by implanting CNE cells. LMP2A specific CTL could inhibit the growth of implanted tumor and produce an anti-tumor effect in vivo.