Development of a nonhuman primate model for dengue virus infection

为建立登革病毒(DV)感染的非人灵长类动物模型，用DV 1型和2型感染恒河猴。DV 1型和2型可引起持续2~3d的病毒血症，平均峰值滴度为4×103RNA拷贝/ml，但感染的猕猴在接种高剂量病毒后仍未表现出登革病的迹象。与源自恒河猴的MDM细胞相比，DV 2型可在帽猴来源的MDM细胞中有效复制。这些结果表明，帽猴可能是一个有用的模型来研究登革热。为了提高森林脑炎病毒(TBEV)的反向遗传学，我们构建了一个由最小巨细胞病毒启动子控制的基于质粒的感染性克隆，编码TBEV全长基因。用该质粒转染细胞，可产生高水平的感染性TBEV。此外，我们还开发了基于同源重组的TBEV和DV的反向遗传学。这里描述的反向遗传学方法可以作为强大的工具用于DV复制和发病机制的研究。

To develop a nonhuman primate model for dengue virus (DV) infection, rhesus monkeys were inoculated with DV types 1 and 2. The DV types 1 and 2 induced viremia with duration from 2 to 3 days and a mean peak titer of 4×10^3 RNA copies/ml but infected monkeys showed no sign of dengue diseases even after inoculation of high virus doses. DV type 2 effectively replicates in MDM cells derived from bonnet monkeys compared to those derived from rhesus monkeys. These results suggest that bonnet monkey may be a useful model to study dengue disease.To improve a reverse genetics for tick-borne encephalitis virus (TBEV) which belongs to the same member of the Flavivirus genus as DV, we have constructed a plasmid-based infectious clone encoding full-length TBEV cDNA under control of the minimum cytomegalovirus promoter. Transfection of cells with the plasmid resulted in the production of infectious TBEV at high levels. Furthermore, we have developed homologous recombination-based reverse genetics for TBEV and DV. The reverse genetics approaches described here can be exploited for studies of DV replication and pathogenesis as powerful tools.