Bat 'super immunity' may explain how bats carry coronaviruses, study finds

研究发现，蝙蝠的‘超级免疫力’也许能帮助我们了解蝙蝠是如何携带冠状病毒的

上海译锐翻译  2020-5-12   13:29 p.m.

A University of Saskatchewan (USask) research team has uncovered how bats can carry the Middle East respiratory syndrome (MERS) coronavirus without getting sick -- research that could shed light on how coronaviruses make the jump to humans and other animals.

萨斯喀彻温大学的研究团队发现了蝙蝠是如何在不生病的情况下携带中东呼吸综合症（MERS）冠状病毒的。该研究也许可以让我们了解冠状病毒是如何感染人类及其他动物的。

Coronaviruses such as MERS, Severe Acute Respiratory Syndrome (SARS), and more recently the COVID19-causing SARS-CoV-2 virus, are thought to have originated in bats. While these viruses can cause serious and often fatal disease in people, for reasons not previously well understood, bats seem unharmed.

诸如中东呼吸综合症、严重急性呼吸道综合症以及最近引起SARS CoV2 病毒的COVID19等冠状病毒被认为来自于蝙蝠。这些病毒能够在人体中引起严重并往往是致命的疾病，但是由于一些此前未知的原因，蝙蝠在这些病毒面前似乎毫发无损。

"The bats don't get rid of the virus and yet don't get sick. We wanted to understand why the MERS virus doesn't shut down the bat immune responses as it does in humans," said USask microbiologist Vikram Misra.

“蝙蝠并没有消除这些病毒，但是同时也没有生病。我们希望弄清楚为什么MERS病毒不会像关闭人类的免疫应答一样关闭蝙蝠的免疫应答”，萨斯喀彻温大学的微生物学家Vikram Misra表示。

immune response：免疫应答（机体对抗原的应答）

In research just published in Scientific Reports, the team has demonstrated for the first time that cells from an insect-eating brown bat can be persistently infected with MERS coronavirus for months, due to important adaptations from both the bat and the virus working together.

"Instead of killing bat cells as the virus does with human cells, the MERS coronavirus enters a long-term relationship with the host, maintained by the bat's unique 'super' immune system," said Misra, corresponding author on the paper. "SARS-CoV-2 is thought to operate in the same way."

在刚刚发表于《科学报告》的研究中，研究团队首次展示了由于蝙蝠和病毒共同作用并发生了一些重要的转变，以昆虫为食的棕色蝙蝠体内的细胞可以在数月内持续受到MERS冠状病毒的感染。“病毒并没有像杀死人类体内的细胞那样消灭蝙蝠体内的细胞，MERS冠状病毒与宿主达成了一项长期的关系，这种关系由蝙蝠独特的‘超级’免疫系统所维持”，论文的通信作者Misra表示。“SARS CoV2被认为以同样的方式发挥作用。”

host:宿主

Misra says the team's work suggests that stresses on bats -- such as wet markets, other diseases, and possibly habitat loss -- may have a role in coronavirus spilling over to other species.

Misra表示，团队的研究显示，蝙蝠所面对的一些应激，比如农贸市场、其他疾病以及可能存在的栖息地的消失都可能在冠状病毒蔓延向其他物种中发挥作用。

"When a bat experiences stress to their immune system, it disrupts this immune system-virus balance and allows the virus to multiply," he said.

“当某只蝙蝠的免疫系统遭遇应激时，它会阻断免疫系统和病毒之间的平衡并导致病毒繁殖”，他表示。

The research was carried out at USask's Vaccine and Infectious Disease Organization -- International Vaccine Centre (VIDO-InterVac), one of the world's largest containment level 3 research facilities, by a team of researchers from USask's Western College of Veterinary Medicine and VIDO-InterVac.

研究在萨斯喀彻温大学疫苗和感染疾病组织国际疫苗中心展开。该中心是全球最大的3级防护研究机构之一。研究由萨斯喀彻温大学西方兽医学院和VIDO InterVac的研究团队展开。

"We see that the MERS coronavirus can very quickly adapt itself to a particular niche, and although we do not completely understand what is going on, this demonstrates how coronaviruses are able to jump from species to species so effortlessly," said VIDO-InterVac scientist Darryl Falzarano, who co-led the bat study, developed the first potential treatment for MERS-CoV, and is leading VIDO-InterVac's efforts to develop a vaccine against COVID-19.

“我们看到MERS冠状病毒能够非常迅速地适应特定的环境。虽然我们还没有彻底明白这其中到底发生了什么，但是我们可以看到冠状病毒是如何能够毫不费力地从某些物种扩散到另一些物种”，VIDO InterVac科学家Darryl Falzarano表示。Darryl Falzarano是蝙蝠研究项目的带头人之一，其推出首个针对MERS CoVD的潜在治疗方案并带领VIDO InterVac研究团队共同研发COVID19的疫苗。

So far, the SARS-CoV-2 virus has infected more than 3.5 million people worldwide and killed seven per cent of those infected. In contrast, the MERS virus infected nearly 2,500 people in 2012 but killed one in every three people infected. There is no vaccine for either SARS-CoV-2 or MERS. While camels are the known intermediate hosts of MERS-CoV, bats are suspected to be the ancestral host.

迄今为止，SARS CoV2病毒已经感染了全球超过3500万人次并且感染人群中的死亡率为7%。相比之下，MERS病毒在2012年所感染的人数接近2500人次，并且每三例感染中就有一例死亡。无论是SARS CoV2，还是MERS，都没有对应的疫苗。骆驼是MERS CoV已知的中间宿主，而蝙蝠则是疑似初宿主。

intermediate host:中间宿主

ancestral host：初宿主

Coronaviruses rapidly adapt to the species they infect, Misra said, but little is known on the molecular interactions of these viruses with their natural bat hosts. A 2017 USask-led study showed that bat coronaviruses can persist in their natural bat host for at least four months of hibernation.

冠状病毒会迅速适应其所感染的物种。Misra表示，目前对于这些病毒与天然蝙蝠宿主之间的分子作用还知之甚少。2017年，一项由萨斯喀彻温大学领衔的研究表明，蝙蝠冠状病毒至少能够在其天然的蝙蝠宿主中蛰伏4个月。

hiberanation：蛰伏

When exposed to the MERS virus, bat cells adapt -- not by producing inflammation-causing proteins that are hallmarks of getting sick, but rather by maintaining a natural antiviral response, a function which shuts down in other species, including humans. Simultaneously, the MERS virus also adapts to the bat host cells by very rapidly mutating one specific gene, he said.

当暴露于MERS病毒时，蝙蝠的细胞不会产生引起炎症的蛋白质（同时也是生病的标志），相反，蝙蝠会保持一种天然的抗病毒响应，一种在其他物种，包括人类都无法激活的功能。同时，MERS病毒还会通过迅速改变某个特定基因的方式来适应蝙蝠宿主的细胞。

Operating together, these adaptations result in the virus remaining long-term in the bat but being rendered harmless until something -- such as disease or other stressors -- upsets this delicate equilibrium.

通过共同作用，这些调整导致病毒长期存在于蝙蝠体内，但是同时不会对蝙蝠造成伤害，直至某些情况，比如疾病或其他应激因素破坏了这一微妙的平衡关系。

Next, the team will turn its focus to understanding how the bat-borne MERS virus adapts to infection and replication in camelid (a group of even-toed ungulates that includes camels) and human cells.

接下来，团队将把研究重点放在了解携带MERS的蝙蝠如何适应感染以及骆驼科和人类细胞的繁殖。

"This information may be critical for predicting the next bat virus that will cause a pandemic," said Misra.

该信息可能对于预测下一个引起传染病的病毒至关重要，Misra表示。

文章来源：科学日报   翻译及编辑：上海译锐翻译质控部