VOA常速英语2016--疟疾疫苗研制取得新进展（在线收听）

疟疾疫苗研制取得新进展

British researchers have discovered a biochemical key used by the malaria parasite to invadehuman blood cells. The discovery could pave the way for an effective malaria vaccine. ThePlasmodium malaria parasite has a complex life cycle, and that gives scientists different targetsfor trying to interrupt its development. One critical point in that process is when the parasiteenters the victim's red blood cells. It does that by interacting with a chemical receptor on thesurface of the cell. Previous research identified several of those receptors, but the problemhas been that if one receptor is blocked, the parasite uses a different one. Now, scientists haveidentified a single blood cell receptor that Plasmodium absolutely needs to enter the bloodcell. Julian Rayner of the Wellcome Trust Sanger Institute in Cambridge says the research teamused different techniques to prove the key role of the receptor, called basigin. And what wediscovered essentially is by adding in protein or antibody in increasing amounts, we couldblock invasion of the red blood cell. Our colleagues, led by Manoj Duraisingh at Harvard, useda genetic approach to create red blood cells with reduced amounts of basigin on the surface,and again that had a big impact on invasion. In the process, Rayner says they used more than15 varieties of the malaria parasite, including some currently circulating in the wild. But this one(basigin) seems to be used by every parasite strain that we've tested to date. And some ofthe ones that we've tested in this paper were in collaboration with scientists in Senegal. Andthese are parasites that are really freshly isolated from people's arms, so they haven't beensitting in a culture dish for a long time. These are real parasites as recently exposed tohumans. Other malaria vaccines are in development, but co-author Gavin Wright expressedconfidence that one based on this discovery might be more successful. We've probably gotmore data to show that this really is a critical interaction than for any other candidate in thepast. So, as a starting point for developing a vaccine, you couldn't hope for better. Theresearchers say a vaccine targeting the basigin receptor may be a decade or more away. Butthey say that unlike vaccines for some other diseases, which are useful only in prevention, amalaria vaccine that targets basigin may also be a useful treatment, blocking the constant re-infection of blood cells that characterizes malaria.

英国研究者发现疟原虫入侵人体血细胞的生物学关键所在。该发现将为疟疾疫苗的研制铺路。抗药性疟原虫性疟疾的生命周期复杂，因此科学家要破坏其生命周期，可以有不同的目标。一个关键点就是疟原虫进入宿主血细胞的时候。疟原虫是通过跟血细胞表面的化学感受器交流来进入血细胞的。此前的研究已证实血细胞表面几个化学感受器的存在，但问题是，倘若阻塞了某个感受器，疟原虫会换一个感受器来接触。如今，科学家确认了一种疟原虫进入血细胞所必须的感受器。英国剑桥大学韦尔科姆基金会桑格学院研究所的朱利安称，研究小组使用了不同的技术来证实这个感受器的主要作用，它叫做basigin蛋白。

我们发现的关键点是，不断增加蛋白质或抗体，就能阻止疟原虫入侵血细胞。而哈佛大学由马努基带领的团队，从基因的角度，通过减少血细胞表面的basigin来增加血细胞。这种做法对疟原虫的入侵也有极大影响。在这个过程中，朱利安表示，他们使用了超过15种疟原虫，其中集中在野生动物身上也广泛存在。而在目前为止的实验中，所有疟原虫都需要使用basigin来进入血细胞。这篇实验论文中提到的一些疟原虫，是我们和塞内加尔的一些科学家合作发现的。这几种病原虫还没能入侵手臂，也就表明他们还没在某个文化存在多久。这些是最近才在人类身上出现的疟原虫。虽然目前尚有其他的疟疾疫苗处于研制阶段，但合著者加文对这次发现能成功研制疫苗的事情很有信心。我们有更多的数据表明，这种化学接收器的对疟原虫的入侵具有重要意义。所以，在研制疫苗的初始阶段能有这样的发现，夫复何求啊。研究人员表示，针对basigin感受器的疫苗可能需要10年甚至更久才能研制成功。但他们表示，疟疾的疫苗不同于其他疾病的疫苗，它不仅对预防有效，还对治疗有效，能阻碍感染疟疾的血细胞再次感染。