VOA慢速英语2020 研究表明T细胞在对抗冠状病毒方面发挥重要作用（在线收听）

What gives some people immunity from the novel coronavirus, the virus that causes COVID-19?

什么使有些人对引发新冠肺炎的新冠病毒具有免疫力？

Some scientists are studying whether it is the presence of antibodies. Others are studying a part of the human immune system, known as T cells, which can protect people from viruses.

一些科学家正在研究抗体是否存在。其他人则在研究人类免疫系统的组成部分——可保护人们免受病毒侵害的T细胞。

Recent studies show that some recovered patients who tested negative for coronavirus antibodies developed T cells in their immune systems. The reaction is believed to be the result of their COVID-19 infection. The studies are small and have yet to be confirmed by outside experts. However, some scientists now say that people who show few signs of sickness from the new coronavirus, or show no signs at all, may be actually killing off the infection with their T cells.

最近的研究表明，一些康复患者在冠状病毒抗体检测中呈阴性，但他们的免疫系统中产生了T细胞。这种反应被认为是他们感染新冠肺炎的结果。这项研究规模很小，而且尚未得到外部专家的证实。然而，现在一些科学家表示，几乎未出现新冠病毒感染迹象或完全没有迹象的人，可能实际上正在用他们体内的T细胞消灭感染。

The findings add to the evidence that an effective COVID-19 vaccine will need to push T cells to work in addition to producing antibodies. This may also affect several treatments that are being developed. The recent findings may explain how immunity to the virus might work.

这项发现补充了证据，证明有效的新冠肺炎疫苗除了产生抗体以外，还需要推动T细胞发挥作用。这可能还会影响目前正在研发的多种治疗方法。这一最近的研究发现可以解释对病毒免疫是如何起作用的。

Dr. Alessandro Sette is studying the reaction to the coronavirus at the La Jolla Institute's Infectious Disease and Vaccine Center in California. He said there is growing evidence that "people exposed to the virus have a transient (short-lived) antibody response," or they have a T cell response without creating antibodies.

亚历桑德罗·塞特博士正在加州拉霍亚研究所的传染病与疫苗中心研究对冠状病毒的反应。他表示，越来越多的证据表明，“接触病毒者会产生短暂的抗体反应”，或是产生T细胞反应而不产生抗体。

When a virus gets past the body's infection-fighting white blood cells, another defense reaction starts. It causes the production of cells that attack the invading virus. The defense includes antibodies that can identify the virus and lock onto it, preventing its entry into a person's cells. The body's defense also can include T cells that can kill both invaders and the cells they have infected.

当病毒通过体内对抗感染的白细胞时，会触发另一个防御反应。这会产生袭击入侵病毒的细胞。防御措施包括识别并锁定病毒的抗体，防止病毒进入人体细胞。人体的防御机制还可包括能杀死入侵者和感染细胞的T细胞。

How effective are antibodies against the coronavirus?

冠状病毒抗体的效果如何？

The world is now six months into the COVID-19 outbreak. The coronavirus has infected more than 12 million people. But scientists are not sure whether the antibody reaction to the virus infection is strong or lasts over time. Some scientists think this could mean T cells have an important job protecting humans against illness.

目前，全球已进入新冠肺炎疫情爆发的第6个月。冠状病毒已经感染了超过1200万人。但科学家仍未确定抗体对新冠病毒感染的反应是强烈的还是会持续一段时间。一些科学家认为这可能意味着T细胞在保护人类抵御疾病方面发挥着重要作用。

"T cells are often important in controlling viral infections. We are seeing evidence of that," John Wherry told Reuters. He is a director of the University of Pennsylvania's Institute for Immunology.

约翰·惠里对路透社表示，“T细胞在控制病毒感染方面通常很重要。我们已经看到了证据。”他是宾夕法尼亚大学免疫学研究所的主任。

Reuters reports that a recent, small French study that has not yet been confirmed by experts, examined immunity in family members. It found that six out of eight family members in close contact with relatives who had COVID-19 developed a T cell response. Importantly, tests did not show that they had coronavirus antibodies.

据路透社报道，法国最近开展了一项尚未得到专家证实的小型研究，对家庭成员的免疫力进行了检测。研究发现，与感染新冠肺炎的亲属密切接触的8名家庭成员中，6人产生了T细胞反应。重要的是，检测显示他们并没有产生冠状病毒抗体。

A Swedish study of about 200 people had similar results. It found a strong T cell response in most individuals who had few or no signs of sickness following coronavirus infection. The T cells were present whether or not any antibody response was found.

一项涵盖约200人的瑞典研究也得出了类似的结果。这项研究发现，大多数感染冠状病毒后几乎没有出现患病症状或完全没有症状的人，出现了强烈的T细胞反应。无论是否有抗体反应，T细胞都存在。

Memories of coronavirus

冠状病毒的记忆

Examining T cell responses could also help explain longer-term immunity.

研究T细胞反应可能也有助于解释长期免疫。

There is some evidence that T cells developed after exposure to other coronaviruses which cause the common cold could help fight off the new virus. The new virus is also known as SARS-CoV-2.

一些证据表明，接触引发普通感冒的其他冠状病毒后产生的T细胞，可能有助于对抗这种新病毒。新病毒又名SARS-CoV-2。

A study by the La Jolla Institute found T cells that reacted to SARS-CoV-2 in about half of stored blood samples collected between 2015 and 2018. That might mean that earlier infections with the common cold coronaviruses might help protect against the new virus.

拉霍亚研究所进行的研究发现，2015年至2018年收集的储存血液样本中，约一半对SARS-CoV-2病毒有反应。这可能表明，普通感冒冠状病毒导致的早期感染可能有助于抵御新病毒。

"It is a potentially encouraging piece of evidence," Wherry said.

惠里表示，“这是潜在的令人鼓舞的证据。”

The current vaccine candidates against COVID-19 aim to create antibody and T cell responses.The recent findings suggest the importance of the T cell response in human medical tests.

目前对抗新冠肺炎的候选疫苗旨在产生抗体和T细胞反应。最近的发现说明了T细胞反应在人类医学测试中的重要性。

"We believe that the optimal vaccine design would be one with both an antibody and T cell response," Sette said.

塞特表示，“我们认为最理想的疫苗设计应该既有抗体又有T细胞反应。”

After an infection or vaccination, the immune system keeps a number of "memory" cells that are ready to quickly attack the same virus in case of a future infection.

在感染或接种疫苗后，免疫系统会保留许多“记忆”细胞，这些细胞随时准备在未来遭遇感染时攻击同一种病毒。

Many countries are using blood tests that look for antibodies to estimate how many people have been infected. But measuring "memory" T cells is much more difficult. It also remains unclear what combination of immune system cells will result in the best protection from the virus.

许多国家正在用血液检测寻找抗体，以估计有多少人被感染。但测量“记忆”T细胞要困难得多。目前仍不清楚哪种免疫系统细胞组合能产生最好的病毒防御效果。

"It is a lot easier to collect antibody data," said Daniela Weiskopf. She is an assistant professor at the La Jolla Institute.

达妮埃拉·韦斯科夫表示，“收集抗体数据要容易得多。”她是拉霍亚研究所的助理教授。

I'm Susan Shand.

苏珊·尚德报道。

Words in This Story

immunity–n. to be unaffected by a disease

negative–adj. a bad reaction

exposed–adj. to be out in the open or available

response–n. an answer or reaction to something

sample–n. a test amount

potentially–adv. possibility

encouraging–adj. a positive sign

optimal–adj. in the best case