经济学人下载:是否有种疫苗能对付毒品滥用？

Science and Technology Combating addiction
科技 打击吸毒

Can a vaccine stop drug abuse?
是否有种疫苗能对付毒品滥用？

It may be possible to vaccinate people against addictive drugs
向吸毒者接种疫苗防止毒瘾将成为可能

THE idea of vaccinating drug addicts against their affliction is an intriguing one.
如何消除吸毒者的毒瘾折磨，是个有挑战性的命题。

In principle, it should not be too hard.
从理论上来讲，这并不难。

The immune system works, in part, by making antibodies that are specific to particular sorts of hostile molecule.
只要让免疫系统，产生某种针对这种恶性分子的抗体便可。

Such antibodies recognise and attach themselves to these molecules, rendering them harmless.
这种抗体能识别并紧紧附在毒品分子上，尽可能消灭它们。

Vaccines work by presenting the immune system with novel targets, so that it can learn to react to them if it comes across them again.
疫苗让免疫系统有了明确的对付目标，系统便能在下次遇到该种病毒时有所反应，将其及时消灭

The problem is that the molecules antibodies recognise and react to are the big ones, such as proteins, that are characteristic of bacteria, viruses and other infectious agents.
问题是，抗体能够识别出较大的分子，比如以蛋白质形式表现出来的，像细菌，病毒，或者别的感染物质。

Small molecules, such as drugs, go unnoticed.
较小的分子，比如毒品，却不能识别出来。

But not for much longer, if Kim Janda of the Scripps Research Institute in San Diego has his way.
不久后这一情况会有所改变，圣地亚哥克里斯普研究所的Kim Janda谈到。

In a paper just published in the Journal of the American Chemical Society, Dr Janda and his colleagues suggest how a vaccine against methamphetamine, a popular street drug, might be made.
近期出版的美国化学学会杂志中，一篇文章提到，Janda博士及他的同事们发现，一种对抗常见毒品甲基苯丙胺的疫苗有望实现。

If their method works, it would open the possibility of vaccinating people against other drugs, too.
以此类推，对抗其他毒品的疫苗也将可能到来。

The idea of a methamphetamine vaccine is not new.
研制对抗甲基苯丙胺的疫苗设想已不是新话题了。

The problem is getting the immune system to pay attention to a molecule that is such a small target.
关键在于免疫系统能“发现”这样小的目标。

The way that has been tried in the past is to build the vaccine from several components.
过去的日子里很多方法都已试验，并从不同角度研发疫苗。

First, there is a large carrier protein that forms a platform for the target.
首先，需要一个蛋白质载体作为平台，让免疫系统能发现毒品分子。

Then there is the target itself, a set of smaller molecules called haptens that are attached to the carrier. These may either be the drug in question or some analogue of it that, for one reason or another, is to have a better chance of training the immune system.
有了目标后，将会有一系列被称作半抗原的分子将会聚集在这些病毒载体上，这些病毒或者类似的分子，无论怎样，有助于提高免疫系统的识别能力。

Finally, there is a chemical cocktail called an adjuvant that helps get the immune system to pay attention to the carrier protein and the haptens.
最后，一种叫佐剂的化学物质，推动免疫系统识别蛋白质载体和半抗原

Dr Janda noticed that past experiments on methamphetamine vaccines had all revolved around tweaking either the carrier protein or the adjuvant, rather than tinkering with the haptens.
Janda博士根据过去针对甲基苯丙胺疫苗的实验发现，该疫苗更多时候是反复出现于蛋白质载体或者佐剂附近，却并非是半抗原的补充作用。

He thought he might be able to change that, on the basis of work he had carried out previously, trying to design a vaccine against nicotine. In particular, nicotine is a highly flexible molecule.
他认为他可以设法改变这一现状。就目前的研发成果的基础上，他正在研发某种对抗尼古丁的疫苗。

That makes it hard for the immune system to recognise.
尤其是，尼古丁是一种较灵活的分子，使免疫系统更加难以识别。

To overcome this, his team on the nicotine project had to work out how to fix their haptens to the carrier protein in a way that rendered them less capable of twisting and turning, and thus made them easier for the immune system to identify.
为克服这一困难， Janda博士的团队已经研究出如何令半抗原附在蛋白质载体上，并让其活动稳定一些。如此，免疫系统便能更好的识别出病毒。

In the new study, Dr Janda and his colleagues report that they have performed a similar trick with methamphetamine haptens.
Janda博士和他的同事们最新研究表示，他们已成功应对甲基苯丙胺半抗原，

They used computer models to visualise the haptens in three dimensions and thus work out how the molecules could be rearranged such that they could not spring, twist or turn when being examined by the immune system.
他们利用电脑模拟视图显示三种形式的半抗原，并证明免疫系统检查人体时，分子可被重新排列并不在复发。

In light of this information they designed six new methamphetamine-like haptens.
据此，他们设计了六种全新的似甲基苯丙胺半抗原。

Once built, they attached the new hapten molecules to carrier proteins, mixed them with adjuvant, injected the results into mice and waited.
之后，他们把这些新的半抗原分子和着佐剂附在蛋白质载体上，并试验于白鼠。

After several weeks they tested the mice to see if the animal's?? blood contained antibodies to methamphetamine.
几周后，他们测试了这些白鼠，看它们血液内是否含有对抗甲基苯丙胺的抗体。

Of the six new haptens, three successfully provoked the mice to make such antibodies.
在这六种半抗原中，有三种成功：小白鼠体内有了抗体。

As a bonus, one of those three also stimulated the production of antibodies against another widely used drug, amphetamine.
在三只中白鼠的一只，其抗体将会被广泛运用，生产对抗另一种药物安非他明的抗体。

That is still a long way from providing a working vaccine, but it is an important step forward.
尽管前路漫漫，但此举终是重要一步。

And if human immune systems react in the same way to the new vaccines as murine ones do, the day when a drug addict might be offered vaccination rather than opprobrium will have come a little closer.
若是人体免疫系统能像小老鼠那样接受疫苗的话，用疫苗解决毒瘾将指日可待。