经济学人下载:疫苗能阻止药物滥用吗?

Science and Technology
科技

Combating addiction
打击毒瘾

Can a vaccine stop drug abuse?
疫苗能阻止药物滥用吗？

It may be possible to vaccinate people against addictive drugs
人们也许能通过疫苗来阻止成瘾药物的使用

THE idea of vaccinating drug addicts against their affliction is an intriguing one.
对药物滥用者进行免疫来对抗他们受到的折磨是一个吸引人的课题。

In principle, it should not be too hard.
原理上，这应该不会太难。

The immune system works, in part, by making antibodies that are specific to particular sorts of hostile molecule.
免疫系统可以部分参与产生那些针对某些有害分子的抗体。

Such antibodies recognise and attach themselves to these molecules, rendering them harmless.
这些抗体可以识别并与那些有害分子结合，使他们变成对身体无害的物质。

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.
疫苗则是通过向免疫系统提供新的靶物质的方法起作用的，因此当免疫系统再次遇到这些物质时，它就会知道该如何作出反应。

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.
问题是抗体能识别和做出反应的分子是大分子，比如蛋白质，这是细菌，病毒和其他致病原的特征。

Small molecules, such as drugs, go unnoticed.
小分子，如毒品，就不被识别了。

But not for much longer, if Kim Janda of the Scripps Research Institute in San Diego has his way.
如果位于圣迭戈斯克里普斯研究所的金-简达有解决办法的话，这种情况就能结束了。

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.
在刚出版的一期《美国化学会会志》中，简达博士在一篇论文中指出了一种对抗街上常见药--甲基苯丙胺的疫苗可以被合成的方法。

If their method works, it would open the possibility of vaccinating people against other drugs, too.
如果他们的方法凑效的话，那将使给人们注射疫苗来对抗其他药物成瘾成为可能。

The idea of a methamphetamine vaccine is not new.
甲基苯丙胺疫苗的想法并非什么新鲜事。

The problem is getting the immune system to pay attention to a molecule that is such a small target.
问题在于要使免疫系统对如此小的目标做出反应。

The way that has been tried in the past is to build the vaccine from several components.
之前曾尝试过的方法是利用几种物质共同构建疫苗。

First, there is a large carrier protein that forms a platform for the target.
首先，要有一个大的载体蛋白来构成给靶物质的平台。

Then there is the target itself, a set of smaller molecules called haptens that are attached to the carrier.
然后是与载体结合的靶物质本身，他们是一组叫做半抗原的较小的分子。

These may either be the drug in question or some analogue of it that, for one reason or another, is reckoned to have a better chance of training the immune system.
这些小分子可以是目标药物或其它一些类似物，他们有这样或那样的理由被认为能够更好地锻炼免疫系统。

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，有一种叫做佐药的鸡尾酒帮助免疫系统对载体蛋白和半抗原做出反应。

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.
简达博士意识到过去对甲基苯丙胺的实验中，疫苗一直在周旋，使载体蛋白或佐药发生扭曲，而非与半抗原互补。

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.
他觉得基于之前所展开的工作，他有能力改善那种情况，并尝试设计出一种对抗尼古丁的疫苗。

In particular, nicotine is a highly flexible molecule.
尼古丁是一种尤其高活性的分子。

That makes it hard for the immune system to recognise.
这使得免疫系统难以识别它。

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.
为了克服这个问题，他的尼古丁项目的团队必须使他们的半抗原以一种特定方式与载体蛋白结合，从而使得这些蛋白不易扭曲反转，从而让免疫系统更容易识别。

In the new study, Dr Janda and his colleagues report that they have performed a similar trick with methamphetamine haptens.
在一篇新的研究中，简达博士和他的同事指出他们用类似的方法处理甲基苯丙胺半抗原。

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.
他们利用电脑模型来展现三维半抗原并解决了分子重新排布的问题，使他们在免疫系统检查时无法弹出，扭曲，旋转。

In light of this information they designed six new methamphetamine-like
在该办法的启发下，他们设计出6种新的甲基苯丙胺样的半抗原。

Once built, they attached the new hapten molecules to carrier proteins, mixed them with adjuvant, injected the results into mice and waited.
一旦构建完成，他们把这些新的半抗原分子结合到载体蛋白上，并与佐药混合，注射进小鼠体内，等待结果。

After several weeks they tested the mice to see if the animals' blood contained antibodies to methamphetamine.
数周后他们检测小鼠血液内是否含有甲基苯丙胺的抗体。

Of the six new haptens, three successfully provoked the mice to make such antibodies.
在6种新的半抗原中，其中3种成功刺激小鼠产生这些抗体。

As a bonus, one of those three also stimulated the production of antibodies against another widely used drug, amphetamine.
另外有一个意外收获，在那3种当中有一种可刺激产生另一种广泛使用的药物--苯丙安的抗体。

That is still a long way from providing a working vaccine, but it is an important step forward.
虽然距离能够供应疫苗的日子还有很长一段路要走，但这是前进中重要的一步。

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.
如果人类免疫系统对新疫苗的反应机制就像鼠科动物那样的话，药物成瘾的人获得的是疫苗而非外界辱骂的这一天的来临就更近了。