由于致病病原體, 如細菌等能夠迅速突變來逃避人體免疫的識別，開發具有廣泛保護作用的免疫疫苗是近年來公共衛生領域研究的熱點。

哈佛大學公共衛生學院研究人員李元博士等人經過多年努力，近日***了免疫系統限制細菌進化過程中一個極為重要的***制。論文在線發表發表在美國《公共科學圖書館*病原體》雜志上，并且成為該雜志被瀏覽次數最多的論文。

研究過程中，李元博士及合作者發現一種特定的人體免疫***制， 細胞免疫，能夠防止肺炎鏈球菌的感染，卻不允許細菌通過突變來逃避識別。

經過深入研究，科學家發現這種細胞免疫具有'愛屋及烏' 的特性：如果一個細菌被這種免疫識別，周圍的其他細菌也會被清除。 這大大的限制了細菌的突變進化。

應用生物信息學的方法和云計算, 研究人員進一步分析了肺炎鏈球菌的基因組序列并發現，這種細胞免疫識別的細菌蛋白的確缺失快速突變的跡象。

哈佛大學醫學院教授麥克思說，這一發現是病原體與人體免疫反應研究的重大突破，將使研究者更高效更高質量地制備新型疫苗，抑制致病細菌對免疫的逃逸。
這將有望使根除細菌性肺炎， 流行性感冒等傳染性疾病真正得到實現。

轉自伍佰藝書畫 www.500art***

英文原文如下：
Efficacy of Vaccine Could be Enhanced by Novel Immunity

Bacteria pathogens evolve particularly fast to avoid recognition by
antibody. It has been a major problem in preventing diseases caused by
infection of, for example, pneumococcus.

Now scientists from Harvard University have published an exciting
study in PLOS Pathogens that suggests a solution: one form of human
immunity can limit pneumococcus infection but seems not to allow the
bacteria to evade easily.

The T cell immunity-based vaccine design is one of the most
significant developments in pneumococcal diseases control in many
years', said lead author Yuan Li, a research fellow at Harvard School
of Public Health (HSPH). 'Our study is first to look how the bacteria
have been responding to this type of immunity in humans.'

Dr. Li, senior author Marc Lipsitch, professor of epidemiology at
HSPH, and collaborators examined all proteins encoded by the bacterial
genome, and found that 58 proteins are commonly recognized by human T
cell immunity.

With the help from a computer cloud of 4708 CPUs, the scientists
implemented a bioinformatics method to assess the signals of evading
immunity by scanning whole genome sequences. Dr. Li and colleagues
found that proteins recognized by T cell immunity show no detectable
signs of being under selective pressure, in sharp contrast to proteins
known to be strong target of antibody.

Although the study suggests escape from T cell immunity may be slower,
Dr. Li urged caution in interpreting his findings since this is the
first study of its kind. Still, he said, 'As we get more and more
certain of how our immune system drives evolution of pathogens, it
means that alternative vaccine design may be more effective.'
from: www.500art***