由于致病病原体, 如细菌等能够迅速突变来逃避人体免疫的识别，开发具有广泛保护作用的免疫疫苗是近年来公共卫生领域研究的热点。

哈佛大学公共卫生学院研究人员李元博士等人经过多年努力，近日***了免疫系统限制细菌进化过程中一个极为重要的***制。论文在线发表发表在美国《公共科学图书馆*病原体》杂志上，并且成为该杂志被浏览次数最多的论文。

研究过程中，李元博士及合作者发现一种特定的人体免疫***制， 细胞免疫，能够防止肺炎链球菌的感染，却不允许细菌通过突变来逃避识别。

经过深入研究，科学家发现这种细胞免疫具有'爱屋及乌' 的特性：如果一个细菌被这种免疫识别，周围的其他细菌也会被清除。 这大大的限制了细菌的突变进化。

应用生物信息学的方法和云计算, 研究人员进一步分析了肺炎链球菌的基因组序列并发现，这种细胞免疫识别的细菌蛋白的确缺失快速突变的迹象。

哈佛大学医学院教授麦克思说，这一发现是病原体与人体免疫反应研究的重大突破，将使研究者更高效更高质量地制备新型疫苗，抑制致病细菌对免疫的逃逸。
这将有望使根除细菌性肺炎， 流行性感冒等传染性疾病真正得到实现。

转自伍佰艺书画 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***