SeMNPV持续性感染的甜菜夜蛾细胞株的建立

在昆虫种群中常常发生杆状病毒持续性感染,持续性感染可转变为增殖性感染而引发病毒流行病。本研究拟建立一个病毒-细胞模型,用于探讨杆状病毒持续性感染分子机制。将甜菜夜蛾核多角体病毒(Spodoptera exigua nucleopolyhedrovirus,SeMNPV)在其宿主细胞Se301中无稀释连续传代以弱化病毒毒力,用传至第8代的SeMNPV感染Se301细胞后,虽然大部分细胞因病毒感染而裂解,但仍有少量细胞存活并可传代培养,该传代细胞株命名为P8-Se301。P8-Se301细胞在对数生长期的群体生长倍增时间为58~65 h,慢于Se301细胞的生长速度。光镜和电镜观察表明,少部分P8-Se301细胞具有病毒发生基质、病毒粒子、多角体等病毒感染特征。终点稀释法和感染中心测定表明,4.14%±0.99%的P8-Se301细胞可持续释放感染性的子代病毒,但该子代病毒在Se301细胞中的复制速度较野生型SeMNPV慢。结果表明,P8-Se301细胞呈现典型的持续性感染特征。

Establishment of SeMNPV persistent infection in Spotoptera exigua cells

Persistent baculovirus infection is observed frequently in insect populations. Persistent infection can be transformed to a replicative and infective state caused by stress factors and plays an important role in regulating the size of insect population and in epizoology of baculoviruses. The aim of this study is to establish a persistently baculovirus-infected cell system to explore the molecular mechanisms of baculoviral persistence. Spodoptera exigua nucleopolyhedrovirus (SeMNPV) was serially undiluted passaged in Se301 cells to reduce virulence. Upon infection of Se301 cells with the SeMNPV up to passage 8, a few cells survived even if most of cells died due to virus infection. The surviving cells were passaged and designated as P8-Se301 cell strain. P8-Se301 cells had a population doubling time of 58-65 hours and grew slower than Se301 cells. Light microscopy and electron microscopy observation showed symptom of baculovirus infection, such as virogenic stroma, viral particles and occlusion bodies, in some of P8-Se301 cells. End-point dilution assay and infectious center assay showed that 4.14% +/- 0.99% cells continually released infectious progeny virus which replicated slower than SeMNPV in Se301 cells. The result indicated that P8-Se301 cells show a typical character trait of baculovirus persistent infection.