Trans-generational viral transmission and immune priming are dose-dependent.
Trans-generational viral transmission and immune priming are dose-dependent.
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DOI：
10.1111/1365-2656.13476
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
K. Wilson;D. Grzywacz;J. Cory;Philip Donkersley;R. I. Graham
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文献类型：
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作者：
K. Wilson;D. Grzywacz;J. Cory;Philip Donkersley;R. I. Graham
越来越明显的是，跨代免疫启动（即亲本免疫经验转移到其后代，导致后代保护免受跨代持续存在的病原体的侵害）不仅在脊椎动物中，而且在无脊椎动物中也是一种常见现象。同样，已知隐性致病性感染可通过各种刺激（包括暴露于异源感染）而“触发”为显性感染。然而，这两种现象很少被同时探讨。作为一个模型系统的非洲粘虫（Spodoptera examputa），爆发性农业害虫，其特有的dsDNA病毒（Spodoptera examputa nucleopolyhedrovirus，SpexNPV），本研究的目的是探讨父母接种剂量对跨代病原体传播和免疫启动（在其最广泛的意义上）的影响。幼虫经口攻击的SpexNPV的五个剂量之一，从这些治疗的幸存者交配，并监测其后代的病毒死亡率。用低病毒剂量攻击的亲本的后代显示出“免疫启动”的证据（即SpexNPV攻击后存活率提高）;相反，用较高病毒剂量攻击的亲本的后代表现出对病毒攻击的更大易感性。大多数子代幼虫死于经口攻击的病毒;相反，用最高剂量攻击的父母的大多数后代被垂直传播的病毒杀死（90%），而不是攻击病毒。这些结果表明，潜在致死性病毒攻毒的结果严重依赖于亲代病毒暴露水平-在极低亲代病毒剂量下增加抗性（与跨代免疫引发一致）或在较高亲代剂量下增加易感性（与病毒触发一致）。我们讨论了这些研究结果的影响，了解自然流行的杆状病毒和使用它们作为生物控制剂。
It is becoming increasingly apparent that trans-generational immune priming (i.e. the transfer of the parental immunological experience to its progeny resulting in offspring protection from pathogens that persist across generations) is a common phenomenon not only in vertebrates, but also invertebrates. Likewise, it is known that covert pathogenic infections may become 'triggered' into an overt infection by various stimuli, including exposure to heterologous infections. Yet rarely have both phenomena been explored in parallel. Using as a model system the African armyworm (Spodoptera exempta), an eruptive agricultural pest, and its endemic dsDNA virus (Spodoptera exempta nucleopolyhedrovirus, SpexNPV), the aim of this study was to explore the impact of parental inoculating-dose on trans-generational pathogen transmission and immune priming (in its broadest sense). Larvae were orally-challenged with one of five doses of SpexNPV and survivors from these treatments were mated and their offspring monitored for viral mortality. Offspring from parents challenged with low viral doses showed evidence of 'immune priming' (i.e. enhanced survival following SpexNPV challenge); in contrast, offspring from parents challenged with higher viral doses exhibited greater susceptibility to viral challenge. Most offspring larvae died of the virus they were orally-challenged with; in contrast, most offspring from parents that had been challenged with the highest doses were killed by the vertically-transmitted virus (90%) and not the challenge virus. These results demonstrate that the outcome of a potentially lethal virus challenge is critically dependent on the level of exposure to virus in the parental generation - either increasing resistance at very low parental viral doses (consistent with trans-generational immune-priming) or increasing susceptibility at higher parental doses (consistent with virus triggering). We discuss the implications of these findings for understanding both natural epizootics of baculoviruses and for using them as biological control agents.