Novella I S, Clarke D K, Quer J, Duarte E A, Lee C H, Weaver S C, Elena S F, Moya A, Domingo E, Holland J J
Department of Biology, University of California, San Diego, La Jolla 92093-0116, USA.
J Virol. 1995 Nov;69(11):6805-9. doi: 10.1128/JVI.69.11.6805-6809.1995.
Continuous, persistent replication of a wild-type strain of vesicular stomatitis virus in cultured sandfly cells for 10 months profoundly decreased virus replicative fitness in mammalian cells and greatly increased fitness in sandfly cells. After persistent infection of sandfly cells, fitness was over 2,000,000-fold greater than that in mammalian cells, indicating extreme selective differences in the environmental conditions provided by insect and mammalian cells. The sandfly-adapted virus also showed extremely low fitness in mouse brain cells (comparable to that in mammalian cell cultures). It also showed an attenuated phenotype, requiring a nearly millionfold higher intracranial dose than that of its parent clone to kill mice. A single passage of this adapted virus in BHK-21 cells at 37 degrees C restored fitness to near neutrality and also restored mouse neurovirulence. These results clearly illustrate the enormous capacity of RNA viruses to adapt to changing selective environments.
水泡性口炎病毒野生型毒株在培养的白蛉细胞中持续、持久复制10个月后，其在哺乳动物细胞中的复制适应性大幅下降，而在白蛉细胞中的适应性则大幅增加。在白蛉细胞持续感染后，其适应性比在哺乳动物细胞中高出200多万倍，这表明昆虫细胞和哺乳动物细胞所提供的环境条件存在极大的选择性差异。适应白蛉的病毒在小鼠脑细胞中的适应性也极低（与在哺乳动物细胞培养物中的情况相当）。它还表现出减毒表型，杀死小鼠所需的颅内剂量比其亲本克隆高出近100万倍。这种适应病毒在37摄氏度的BHK - 21细胞中传代一次后，适应性恢复到接近中性水平，同时也恢复了小鼠神经毒力。这些结果清楚地说明了RNA病毒适应不断变化的选择性环境的巨大能力。
