阻断bba64基因表达 开发莱姆病疫苗新策略

科学家提出，让通过虱子传播的莱姆病病源体——莱姆病螺旋体（Borrelia burgdorferi）的一个基因不再活动可以阻止这种疾病的传播。此前的研究表明莱姆病螺旋体的bba64基因在进食的虱子体内表达，然而这种基因的功能尚不为人所知。

Robert Gilmore, Jr及其同事为小鼠注射了一种莱姆病螺旋体菌株，这种修改后的菌株的bba64基因被关闭了，然后让虱子以小鼠为食并获得了这种细菌。

这组科学家然后把这些虱子转移给了没有莱姆病的虱子，结果发现8周后15只实验小鼠只有2只感染了莱姆病。这组作者还从一只未被感染的实验小鼠身上的虱子获取了这种经过遗传修饰的细菌并且重新培养，然后为另一组没有莱姆病的小鼠进行了注射。这组作者说，所有接受注射的小鼠感染了该病，显示出bba64基因很可能对于让虱子仅仅通过叮咬而感染宿主是必不可少的。

这组科学家提出，阻断bba64基因可能带来一种开发莱姆病疫苗的新策略。

点击此处下载原文

The bba64 gene of Borrelia burgdorferi, the Lyme disease agent, is critical for
mammalian infection via tick bite transmission

The spirochetal agent of Lyme disease, Borrelia burgdorferi, is transmitted by bites of Ixodes ticks to mammalian reservoir hosts and humans. The mechanism(s) by which the organism is trafficked from vector to host is poorly understood. In this study, we demonstrate that a B. burgdorferi mutant strain deficient in the synthesis of the bba64 gene product was incapable of infecting mice via tick bite even though the mutant was (i) infectious in mice when introduced by needle inoculation, (ii) acquired by larval ticks feeding on infected mice, and (iii) able to persist through tick molting stages. This finding of a B. burgdorferi gene required for pathogen transfer and/or survival from the tick to the susceptible host represents an important breakthrough toward understanding transmission mechanisms involved for the Lyme disease agent.