健康的微生物群落可以讓身體的免疫系統強大，有助於擊敗新冠病毒的感染

您可能不知道，在你的身體內生活著很多的微生物，這些微生物對於身體抵禦各種威脅（包括導致新冠肺炎的病毒）至關重要。

在過去的二十年中，科學家們瞭解到在我們身體裡面存在的各種細菌細胞比我們人類自己的細胞還要多。這些生活在我們體內和表皮上的細菌群落被稱為微生物組，它們就像一家公司一樣有序地執行著，每種微生物都從事自己特定的工作，但所有微生物的工作合在一起就保持了我們身體的健康。在腸道中的眾多細菌起到了平衡身體對病原體的免疫反應的作用，這些細菌確保我們身體的免疫反應在有效壓制病原體的同時不會反應過度而給我們的身體帶來附加的傷害。

我們腸道中的細菌不僅可以觸發針對感染腸道的病毒（例如諾如病毒和輪狀病毒）的有效免疫反應，還可以引發針對感染肺部的病毒（如流感病毒）的有效免疫反應。有益的腸道微生物透過讓特定免疫細胞產生有效的抗病毒蛋白來最終消除病毒的感染，如果一個人身體裡面缺乏這些有益的腸道細菌，那麼他（她）的身體對入侵病毒的免疫反應就不會那麼強，這樣的結果就是身體可能會無法有效地控制住病毒的感染，從而導致健康受損。

我們的免疫防禦系統是身體針對有害病原體（如病毒或細菌）的複雜生物反應的一部分。但是，由於我們的身體上居住著數以萬億計的有益細菌，病毒和真菌，要區分出哪些是有害微生物和哪些是有益微生物，我們身體必須對在什麼時候啟用免疫反應有著嚴密的把控。

作為重要的夥伴，我們身體裡的細菌一直在辛勤地工作，幫助我們增強免疫系統的防禦能力以抵抗各種感染。有一項具有開創性的研究發現，在用抗生素消除小鼠腸道細菌後，小鼠的免疫反應出現了受損的跡象，這些動物的抗病毒白細胞數量降低，抗體反應變弱，產生某種對於抵抗病毒感染和調節免疫反應至關重要的蛋白質的能力也變差了。

在一篇尚未進行同行評審的論文中，我們證明了與患者通常使用的臨床特徵相比，腸道微生物群落的構成是預測患者新冠肺炎嚴重程度的最強指標。具體來說，我們確定糞便中存在的一種叫做“糞腸球菌”的細菌是預測新冠肺炎嚴重程度的可靠預測指標。這一點都不奇怪，一直以來人們都知道糞腸球菌與慢性炎症有著關聯。

在開始閱讀英文原文之前，請先複習下列核心詞彙：

healthy - adj. 健康的

strong - adj. 強壯的，強烈的

immune - adj. 免疫的

immune system - 免疫系統

microbe - n. 微生物

virus - n. 病毒

bacterial - adj. 細菌的

gut - n. 消化道，腸道，內臟

balance - n. 平衡

pathogen - n. 病原體

collateral - adj. 附屬的，附帶的

collateral damage - 附帶損傷

host - n. 宿主，主人，東道主

infect - v. 感染

lung - n. 肺

flu - n. 流感

viral - adj. 病毒的

infection - n. 感染

viral infection - 病毒感染

beneficial - adj. 有益的

fungus - n. 真菌，黴菌

fungi - fungus的複數

activation - n. 啟發，觸發

diligently - adv. 勤勉地，勤奮地

seminal - adj. 影響深遠的

impair - v. 損害，削弱

vital - adj. 對…極重要的

combat - v. 防止，減輕，戰鬥

modulate - v. 調節，調整

composition - n. 成分，構成

microbiome - n, 微生物組，微生物群系

predictor - n. 預測器，預示物

bacterium - n. 細菌；bacteria的單數

stool - n. 凳子，大便，糞便

chronical - adj. 長期延續的，慢性的

inflammation - n. 發炎，炎症

在複習了以上詞彙後，請將下面的英文原文一口氣讀完，不要在中途停下來去查那些不認識的單詞。有了上面的核心單詞打底，你完全可以將整篇文章讀完並且理解裡面的大致意思。記住，你只要做到大致明白就可以了。

閱讀能力和閱讀量成正比，要提高閱讀量，必須是大量的泛讀，如果要對每個不懂的單詞都去查字典，那麼就不可能透過大量的泛讀來提高你的閱讀量。

A healthy microbiome builds a strong immune system that could help defeat COVID-19

Ana Maldonado-Contreras

Assistant Professor of Microbiology and Physiological Systems

University of Massachusetts Medical School

You may not know it, but you have an army of microbes living inside of you that are essential for fighting off threats, including the virus that causes COVID-19.

In the past two decades scientists have learned our bodies are home to more bacterial cells than human ones. This community of bacteria that lives in and on us – called the microbiome – resembles a company, with each microbe species performing specialized jobs but all working to keep us healthy. In the gut, the bacteria balance the immune response against pathogens. These bacteria ensure the immune response is effective but not so violent that it causes collateral damage to the host.

Bacteria in our guts can elicit an effective immune response against viruses that not only infect the gut, such as norovirus and rotavirus, but also those infecting the lungs, such as the flu virus. The beneficial gut microbes do this by ordering specialized immune cells to produce potent antiviral proteins that ultimately eliminate viral infections. And the body of a person lacking these beneficial gut bacteria won't have as strong an immune response to invading viruses. As a result, infections might go unchecked, taking a toll on health.

Our immune defense is part of a complex biological response against harmful pathogens, such as viruses or bacteria. However, because our bodies are inhabited by trillions of mostly beneficial bacteria, virus and fungi, activation of our immune response is tightly regulated to distinguish between harmful and helpful microbes.

Our bacteria are spectacular companions diligently helping prime our immune system defenses to combat infections. A seminal study found that mice treated with antibiotics that eliminate bacteria in the gut exhibited an impaired immune response. These animals had low counts of virus-fighting white blood cells, weak antibody responses and poor production of a protein that is vital for combating viral infection and modulating the immune response.

We demonstrated, in a paper which has not yet been peer reviewed, that the composition of the gut microbiome is the strongest predictor of COVID-19 severity compared to patient's clinical characteristics commonly used to do so. Specifically, we identified that the presence of a bacterium in the stool – called Enterococcus faecalis– was a robust predictor of COVID-19 severity. Not surprisingly, Enterococcus faecalis has been associated with chronic inflammation.