More than 80 percent of human immunodeficiency virus (HIV) infections are transmitted via sexual intercourse. And researchers may have discovered at least one reason why. According to a new study published in Cell, a component of human semen may facilitate the spread of the virus by targeting immune system cells, in some cases making the pathogen up to 100,000 times more virulent.
The team of German scientists had initially set out to determine if semen contained factors that inhibit the HIV infection. "We were not expecting to find an enhancer, and we were even more surprised about the strength," says report co-author Frank Kirchhoff, a virologist at the University of Ulm Clinic in Germany. "Most enhancers have maybe a two- or three-fold effect, but here the effect was amazing—more than 50-fold and, under certain conditions, more than 100,000-fold."
HIV, the virus that leads to AIDS, has infected 60 million people worldwide (causing 25 million d
80%以上的人类免疫缺陷症感染是通过性接触传递的，研究者可能已经发现至少一条原因来支持它。根据一项刊登在CELL上的新研究表明，人类精液中有种成分也许会通过琐定免疫系统细胞而促使HIV的扩散，在一些情况下使得传染源的烈性达到原来的100000倍。
一组德国科学家已经开始着手推断是否精液里含有一些因子能够抑制HIV的传染。据德国的Ulm临床大学通讯合作作者Frank Kirchhoff说：“我们没有期望能找到一个促进因子，我们甚至更惊奇他们的力量，”多数促进因子可以使得作用提高2到3倍，但是在这里这种作用很神奇，能提高50倍，在特定情况下，多余100000倍。
从1981年这个病毒被发现，在全世界，HIV已经使得全球60万人(其中有25万人死亡)。阴道内性接触的传播率被认为是从1/200到1/2000。在非洲，60%的新感染是在那些与HIV阳性男人做爱后的妇女。
Kirchhoff和他的团队通过对精液中900种蛋白质进行筛选来寻找潜在的控制HIV传播的抑制因子和促进因子。在揭晓的促进因子中，有些是一种叫做前列腺酸性磷酸酶的片段，这种蛋白质是由前列腺分泌的。精液中的肽结构分析表明这种片段与相似一种相似的片段连接在一起可以产生一种淀粉纤维(一段与阿滋海默症有关的蛋白片段)。科学家们把这种淀粉纤维称作“病毒感染的精液驱动促进因子”(SEVI)。研究者表明，如果它们不连接形成纤维，肽片段不会受到影响，并且不会促进病毒传染。
【附】原文如下：
Male Semen Makes HIV More Potent
More than 80 percent of human immunodeficiency virus (HIV) infections are transmitted via sexual intercourse. And researchers may have discovered at least one reason why. According to a new study published in Cell, a component of human semen may facilitate the spread of the virus by targeting immune system cells, in some cases making the pathogen up to 100,000 times more virulent.
The team of German scientists had initially set out to determine if semen contained factors that inhibit the HIV infection. "We were not expecting to find an enhancer, and we were even more surprised about the strength," says report co-author Frank Kirchhoff, a virologist at the University of Ulm Clinic in Germany. "Most enhancers have maybe a two- or three-fold effect, but here the effect was amazing—more than 50-fold and, under certain conditions, more than 100,000-fold."
HIV, the virus that leads to AIDS, has infected 60 million people worldwide (causing 25 million d
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