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Science & technology
科技板块
Immunology
免疫学
Fed by the hand that should bite it
已攻击自己的东西为食
A bacterium that tricks the immune system into nurturing it
一种欺骗免疫系统培养它的细菌
The immune system has many weapons with which to counter hostile incomers.
免疫系统有许多武器可以用来对抗敌对的入侵者。
But what works against one may not be effective against another.
但对一种病毒起作用的方法对另一种可能不起作用。
An interloper can take advantage of this by misdirecting the system into thinking it is fighting an enemy that it is not.
入侵者可以利用这一点，误导系统，让它们认为自己正在与另一个敌人作战，而实际上并非如此。
This buys time for that interloper to become entrenched.
这为闯入者扎根赢得了时间。
That is sneaky.
这太狡猾了。
Sneakier still, though, is the approach just discovered by Ruslan Medzhitov of Yale University.
不过，耶鲁大学的鲁斯兰·梅德日托夫刚刚发现的方法更“狡猾”。
As he and his colleagues report in Immunity, they have found a bacterium that induces its host’s immune system to release compounds on which it can then feed.
正如他和他的同事在《免疫》杂志上报道的那样，他们发现了一种细菌，它可以诱导宿主的免疫系统释放出化合物，并以此为食。
Mammalian immune systems have two modes of attack.
哺乳动物的免疫系统有两种攻击模式。
Type-1 is used against bacteria and viruses; type-2 against multicellular parasites such as worms.
类型1用于对抗细菌和病毒；类型2用于对抗多细胞寄生虫，如蠕虫。
Some invading bacteria, however, provoke a type-2 response when type-1 would be appropriate.
然而，一些入侵的细菌会在适合类型1的攻击模式下引发类型2的反应。
Dr Medzhitov decided to take a closer look.
梅德日托夫博士决定更进一步观察。
He and his colleagues studied the behaviour of Pseudomonas aeruginosa, a bacterium which causes stubborn infections in people with cystic fibrosis.
他和他的同事研究了铜绿假单胞菌的行为，这是一种导致囊性纤维症患者顽固感染的细菌。
They suspected it was leading the body to mount an ineffective type-2 response against it and wanted to know how it was doing this.
他们怀疑这是导致身体对它进行无效的2型反应，并想知道它是如何做到这一点的。
To explore the matter, they grew laboratory cultures of the sorts of epithelial cells that line human airways and monitored their gene-expression profiles when exposed to LasB, a toxic enzyme produced by the bacterium.
为了探究这一问题，他们在实验室培养了人体呼吸道内的各种上皮细胞，并监测了它们在接触LasB时的基因表达谱，LasB是一种由细菌产生的有毒酶。
They found that LasB activated signalling pathways which drove the epithelial cells to make a protein called amphiregulin.
他们发现LasB激活了信号通路，驱动上皮细胞产生一种名为双调节蛋白的蛋白质。
This forms the basis of a thick mucus that excels at ensnaring parasitic worms.
这形成了厚厚的粘液的基础，这种粘液擅长诱捕寄生虫。
It also recruits immune cells called eosinophils, which are adept at attacking multicellular parasites.
它还影响了被称为嗜酸性粒细胞的免疫细胞，这种细胞擅长攻击多细胞寄生虫。
