英国《自然—医学》杂志刊登一项最新研究报告说，美国研究人员研发出一种新型肺结核疫苗，动物实验显示它比现有的卡介疫苗效果更好。
结核分枝杆菌
美国爱因斯坦医学院的研究人员通过细菌基因改造，开发出了这种新型疫苗，并将其命名为IKEPLUS。
肺结核由结核分枝杆菌引起，结核分枝杆菌有一个“亲戚”叫做耻垢分枝杆菌，它们都拥有一个名为esx-3的基因。研究人员发现，如果将耻垢分枝杆菌中的这个基因去除，转而植入来自结核分枝杆菌的同一基因，最终得到的细菌可作为疫苗使用。
动物实验显示，在同样感染结核分枝杆菌的情况下，未注射任何疫苗的实验鼠平均存活时间为54天，注射卡介疫苗的实验鼠平均存活时间为65天，而注射该新型疫苗的平均存活时间长达135天。
领导该研究的威廉·雅各布教授说，新型疫苗的作用原理与已有肺结核疫苗不同，实验显示它比卡介疫苗的效果更好，研究人员将在此基础上开发能用于人体的疫苗。
生物探索推荐英文论文摘要：
We report the involvement of an evolutionarily conserved set of mycobacterial genes, the esx-3 region, in evasion of bacterial killing by innate immunity. Whereas high-dose intravenous infections of mice with the rapidly growing mycobacterial species Mycobacterium smegmatis bearing an intact esx-3 locus were rapidly lethal, infection with an M. smegmatis Δesx-3 mutant (here designated as the IKE strain) was controlled and cleared by a MyD88-dependent bactericidal immune response. Introduction of the orthologous Mycobacterium tuberculosis esx-3 genes into the IKE strain resulted in a strain, designated IKEPLUS, that remained susceptible to innate immune killing and was highly attenuated in mice but had a marked ability to stimulate bactericidal immunity against challenge with virulent M. tuberculosis. Analysis of these adaptive immune responses indicated that the highly protective bactericidal immunity elicited by IKEPLUS was dependent on CD4+ memory T cells and involved a distinct shift in the pattern of cytokine responses by CD4+ cells. Our results establish a role for the esx-3 locus in promoting mycobacterial virulence and also identify the IKE strain as a potentially powerful candidate vaccine vector for eliciting protective immunity to M. tuberculosis.
