时差N小时 血型不是问题（在线收听）

Yael: I just read about an exciting technique. Researchers found a way to convert types A and B blood into type O blood—the type that can be transfused into any patient. This advance could help avoid blood shortages in the future.

雅艾尔：我刚刚读了一条振奋人心的技术。研究人员找到了一种可以把A型、B型血转变为O型血的方法。而O型血可以输给任何病人。这项先进的技术能够避免出现缺血的情况。

Don: Wow, that is exciting. But what makes type O blood so special?

唐：哇，太振奋人心了。但为什么O型血这么特殊呢？

Yael: Blood types result from different carbohydrates, called antigens, on the surface of human blood cells. Your blood "type" denotes the kinds of antigens you have on the surface of your cells. People with type A blood have A antigens; those with type B have B antigens. If you have both kinds of antigens, you're type AB; if you have neither one, you're type O.

雅艾尔：血型因不同的碳水化合物而产生，这种关键的碳水化合物就是抗原，它长在人体血细胞的表面。你的血型表示你的血细胞表面有哪种抗体。A血型的人有A抗体；B血型的人有B抗体。如果你有A和B两种抗体，那你就是AB血型的人；如果二者都没有，那你就是O型血了。

Your immune system recognizes the antigens on your blood as "self", but attack cells with "foreign" antigens. So if you ever need a blood transfusion, it's important that you only receive blood compatible with your own type.

免疫系统把血液中的这些抗体认作"自己人"，却会攻击那些带有"外来"抗体的细胞。因此，如果你需要输血时，你只能接受与自己血型相同的血，这很重要。

Don: I see. So if a type A person receives type B or AB blood, her immune system will see the B-antigens as foreign, and attack the donor blood cells?

唐：我明白了。所以如果A型血的人接受了B型血或者AB型血，她的免疫系统会视B抗体为外来者，于是就会攻击供体的血细胞。

Yael: Exactly. But type O is called the "universal donor" since it doesn't have any antigens that would set off the body's defense system.

雅艾尔：正是如此。O型血之所以被称为"万能血"，是因为它没有任何抗体，不会和身体的防卫系统相抵触。

A team of Danish scientists has identified enzymes that remove the A and B antigens from blood cells. The enzymes, which were extracted from a bacteria and a fungus, essentially change any donated blood into type O.

一个丹麦科学家小组已经找到了一种可以消除细胞中A、B抗体的酶。这种酶是从一种细菌和真菌中提取出来的, 可以把献血者的血型完全变成O型。

Clinical trials are underway to test whether the treated blood is safe and effective. If so, the technology could help save lives, since type O blood is such a precious commodity.

临床试验正在测试这种转化后的血是否安全有效。如果没什么问题，这项技术将挽救不少性命，因为O型血确实很紧缺。