Studies on Pathogenesis of Chronic Active Epstein-Barr Virus Infection

慢性活动性eb病毒（EBV）感染（CAEBV）是一种常见于儿童的致死性t或nk淋巴细胞增生性疾病。本研究旨在阐明CAEBV的未知发病机制，并由此建立一种新的治疗策略。本研究采用的方法是寻找一个潜伏的EBV基因(s)负责不受控制的t或nk细胞增殖，它可以在来自CAEBV患者的病毒阳性t或nk细胞系中取代整个EBV基因组的作用。我们制备了改良的自灭活逆转录病毒载体（sin - rv），可以表达EBV潜伏基因EBNA1、LMP1、LMP2A、BARF0、A73、RPMS1和EBERs。此外，我们成功构建了EBNA1突变体，并将其整合到纤维替代的腺病毒5型载体（Adv5/35f-DNE1）中。Adv5/35f-DNE1证明EBNA1突变体有效地从感染细胞中根除EBV发作，并同时阻碍EBV阳性t或nk细胞系的病毒依赖性侵袭性生长表型，从而表明我们的EBNA1突变体可以作为显性阴性（dn） EBNA1。基于上述数据，我们刚刚进入了鉴定eb病毒潜伏基因对t细胞或nk细胞增殖至关重要的实验的最后阶段。同时，我们正在研究我们的dnEBNA1是否会提供一种额外的治疗分子，专门针对ebv相关的恶性肿瘤，通过一些方式包括动物实验。

Chronic active Epstein-Barr virus(EBV) infection(CAEBV) is a lethal T-or NK-lymphoproliferative disease often occurring in children. This study aimed to clarify the unknown pathogenesis of CAEBV, from which the establishment of a novel remedial strategy against the disease will also benefit.The approach undertaken in this study is to seek for a latent EBV gene(s) resposible for uncontrolled T-or NK-cell-proliferation, which can functionally replace the role of entire EBV genome in the virus-positive T-or NK-cell lines derived from patients with CAEBV. We prepared improved self-inactivating retroviral vectors(SIN-RVs) that can express individual EBV latent genes, e.g., EBNA1, LMP1, LMP2A, BARF0, A73, RPMS1 and EBERs. Also, we successfully constructed an EBNA1 mutant, and incorporated it into the fiber-replaced adenovirus type 5 vector(Adv5/35f-DNE1). Adv5/35f-DNE1 proved that the EBNA1 mutant efficiently eradicates EBV episomes from infected cells and concomitantly impedes the virus-dependent aggressive growth phenotypes of EBV-positive T-or NK-cell lines, thereby indicating that our EBNA1 mutant can act as a dominant-negative(dn) EBNA1.Based on the above data, we have just entered the final aspect of experiments to identify the EBV latent gene(s) essential to T-or NK-cell-proliferation. In parallel, we are invetigating now into whether our dnEBNA1 will provide an additional therapeutic molecule specifically targeting EBV-associated malignancies, by some ways including animal experiments.