Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, 300 Cedar Street, PO Box 208022, New Haven, Connecticut 06520-8022, USA.
EMBO Rep. 2011 Oct 28;12(11):1196-203. doi: 10.1038/embor.2011.177.
Ixodes ticks harbour several human pathogens belonging to the order Rickettsiales, including Anaplasma phagocytophilum, the agent of human anaplasmosis. When ticks feed on A. phagocytophilum-infected mice, the pathogen enters the ticks' gut. The bacteria then migrate from the gut to infect the salivary glands of the ticks and are transmitted to the next host via the saliva. The molecular mechanisms that enable the migration of A. phagocytophilum from the gut to the salivary glands are poorly understood. Here we show that a secreted tick protein, P11, is important in this process. We show that P11 enables A. phagocytophilum to infect tick haemocytes, which are required for the migration of A. phagocytophilum from the gut to the salivary glands. Silencing of p11 impaired the A. phagocytophilum infection of tick haemocytes in vivo and consequently decreased pathogen infection of the salivary glands. In vitro experiments showed that P11 could bind to A. phagocytophilum and thus facilitate its infection of tick cells. This report provides new insights into A. phagocytophilum infection of ticks and reveals new avenues to interrupt the life cycle of Anaplasma and related Rickettsial pathogens.
硬蜱携带几种属于立克次体目（Rickettsiales）的人类病原体，包括嗜吞噬细胞无形体（Anaplasma phagocytophilum），这是人类无形体病的病原体。当蜱吸食感染嗜吞噬细胞无形体的老鼠时，病原体进入蜱的肠道。然后，细菌从肠道迁移到蜱的唾液腺并通过唾液传播给下一个宿主。使嗜吞噬细胞无形体从肠道迁移到唾液腺的分子机制尚不清楚。在这里，我们表明一种分泌的蜱蛋白 P11 在这个过程中很重要。我们表明 P11 使嗜吞噬细胞无形体能够感染蜱的血淋巴细胞，这是嗜吞噬细胞无形体从肠道迁移到唾液腺所必需的。p11 的沉默削弱了嗜吞噬细胞无形体对蜱血淋巴细胞的感染，从而降低了病原体对唾液腺的感染。体外实验表明 P11 可以与嗜吞噬细胞无形体结合，从而促进其感染蜱细胞。本报告为嗜吞噬细胞无形体感染蜱提供了新的见解，并揭示了中断无形体和相关立克次体病原体生命周期的新途径。
