PDF(Pubmed)
Abstract：
Kemerovo virus (KEMV) is a tick-borne orbivirus transmitted by ticks of the genus Ixodes. Previous animal experimentation studies with orbiviruses, in particular the interferon receptor double knock-out (IFNAR(-/-)) mouse model, did not indicate bias that is related to age or sex. We endeavoured to assess the effect of serial and alternated passages of KEMV in mammalian or Ixodes cells on virus replication and potential virulence in male or female IFNAR(-/-) mice, with important age differences: younger males (4-5 months old), older males (14-15 months old), and old females (14-15 months old). After 30 serial passages in mammalian or tick cells, or alternated passages in the two cell types, older female mice which were inoculated with the resulting virus strains were the first to show clinical signs and die. Younger males behaved differently from older males whether they were inoculated with the parental strain of KEMV or with any of the cell culture-passaged strains. The groups of male and female mice inoculated with the mammalian cell culture-adapted KEMV showed the lowest viraemia. While older female and younger male mice died by day 6 post-inoculation, surprisingly, the older males survived until the end of the experiment, which lasted 10 days. RNA extracted from blood and organs of the various mice was tested by probe-based KEMV real-time RT-PCR. Ct values of the RNA extracts were comparable between older females and younger males, while the values for older males were >5 Ct units higher for the various organs, indicating lower levels of replication. It is noteworthy that the hearts of the old males were the only organs that were negative for KEMV RNA. These results suggest, for the first time, an intriguing age- and sex-related bias for an orbivirus in this animal model. Changes in the amino acid sequence of the RNA-dependent RNA polymerase of Kemerovo virus, derived from the first serial passage in Ixodes cells (KEMV Ps.IRE1), were identified in the vicinity of the active polymerase site. This finding suggests that selection of a subpopulation of KEMV with better replication fitness in tick cells occurred.
摘要：
克麦罗沃病毒（KEMV）是通过Ixodes属的蜱传播的蜱传播的Orbivirus病毒。以前用Orbivirus进行的动物实验研究，特别是干扰素受体双敲除（IFNAR（-/-））小鼠模型，没有表明与年龄或性别有关的偏见。我们努力评估KEMV在哺乳动物或Ixodes细胞中的连续和交替传代对雄性或雌性IFNAR（-/-）小鼠的病毒复制和潜在毒力的影响，具有重要的年龄差异：年轻男性（4-5个月大），老年男性（14-15个月大），和老年女性（14-15个月大）。在哺乳动物或蜱细胞中连续传代30次后，或者在两种细胞类型中交替传代，接种了由此产生的病毒株的老年雌性小鼠是第一个出现临床症状并死亡的小鼠。无论是接种KEMV亲本菌株还是接种任何细胞培养传代菌株，年轻男性的行为都与老年男性不同。接种了适应哺乳动物细胞培养的KEMV的雄性和雌性小鼠组显示出最低的病毒血症。虽然年长的雌性和年轻的雄性小鼠在接种后第6天死亡，令人惊讶的是,年长的雄性一直存活到实验结束,持续了10天。通过基于探针的KEMV实时RT-PCR测试从各种小鼠的血液和器官提取的RNA。RNA提取物的Ct值在老年女性和年轻男性之间相当，虽然老年男性的值比各种器官的高>5Ct单位，表明复制水平较低。值得注意的是，老年男性的心脏是唯一对KEMVRNA呈阴性的器官。这些结果表明,第一次,在这种动物模型中，对Orbivirus的年龄和性别相关偏见很有趣。克麦罗沃病毒RNA依赖性RNA聚合酶氨基酸序列的变化,源自Ixodes细胞的第一次连续传代(KEMVPs。IRE1),在活性聚合酶位点附近被鉴定。这一发现表明，在蜱细胞中选择了具有更好复制适应性的KEMV亚群。
