EB病毒膜抗原的表达致转基因小鼠发生淋巴瘤的观察

目的：研究转基因小鼠EB病毒膜抗原（membrane antigen,MA）BLLF1基因的表达与淋巴瘤的关系，探讨EB病毒BLLF1基因作为淋巴瘤致癌基因的可能性。方法（1）观察4只EB病毒膜抗原（MA）BLLF1基因转基因首建鼠（Founder)淋巴瘤的发病时间、发病频率。（2）对发病小鼠进行解剖，观察肿瘤发生部位及特征，取肿瘤组织进行病理学观察。（3）用流式细胞仪分析MA在瘤细胞中的表达并用激光共聚焦显微镜分析MA在瘤细胞中的表达部位。（4）对瘤细胞用碘化丙啶（PropidiumIodide,PI)染色，用激光共聚焦显微镜观察细胞核形改变。（5）用异硫氰酸荧光素（FITC）标记的抗CD3单抗及抗SIgM多抗染色，分析瘤细胞的免疫表型。结果（1）4只转基因首建鼠中，2只MA表达阳性鼠分别在4月龄和8月龄时发生淋巴瘤，而2只MA表达阴性小鼠同期内未发生淋巴瘤，发病率为2／4。（2）组织病理学检查及瘤细胞免疫表型分析证明为T细胞淋巴瘤。（3）流式细胞仪分析表明MA在瘤细胞中表达，激光共聚焦显微镜观察证明MA表达部在细胞及细胞膜上。（4）碘化丙啶（PI）染色后，用激光共聚焦显微镜观察证明MA表达部位在细胞浆及细胞膜上。（4）碘化丙啶（PI）染色后，用激光共聚焦显微镜观察细胞核呈分叶状改变，符合癌细胞核形特点。结论EB病毒膜抗原（MA）BLLFI基因的表达可导致转基因小鼠发生淋巴瘤，提示EB病毒BLLF1基因可能为淋巴瘤的致癌基因。

Expression of Epstein-Barr virus membrane antigen induces lymphoma in transgenic mice

OBJECTIVE: To study the relation between the expression of Epstein-Barr virus (EBV) membrane antigen (MA) and lymphoma and to explore the potentiality of EBV BLLF1 as an oncogene for lymphoma. METHODS: Four transgenic founder mice with EBV MA BLLF1 were created. The development of lymphoma, confirmed by pathology, among them was observed. Flow cytometry was used to analyze the expression of MA in lymphoma cells, and con-focal microscopy was used to localize the expression and observe the nuclei after propidium iodide staining. The immunophenotype of lymphoma cells was analyzed by immunofluorescent technique. RESULTS: Two of the transgenic mice succumbed to lymphoma, confirmed as T cell lymphoma by histopathology and immunophenotypic analysis, at the ages of 4 and 8 months respectively, which were confirmed as MA expression positive. The other 2 MA negative mice remained healthy without lymphoma at the same periods. MA was expressed in the cytoplasm and cytomembrane of the lymphoma cells. Lobulated modification was found in the nuclei of the tumor cells. CONCLUSION: The expression of MA induces lymphoma in transgenic mice. BLLF1 gene is likely an oncogene for lymphoma.