Hidano A, Konnai S, Yamada S, Githaka N, Isezaki M, Higuchi H, Nagahata H, Ito T, Takano A, Ando S, Kawabata H, Murata S, Ohahsi K
Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Insect Mol Biol. 2014 Aug;23(4):466-74. doi: 10.1111/imb.12101. Epub 2014 Apr 4.
Salp16, a 16-kDa tick salivary gland protein, is known to be the molecule involved in the transmission of Anaplasma phagocytophilum, an obligate intracellular pathogen causing zoonotic anaplasmosis, from its mammalian hosts to Ixodes scapularis. Recently, the presence of A. phagocytophilum was documented in Japan and Ixodes persulcatus was identified as one of its vectors. The purpose of this study was to identify Salp16 genes in I. persulcatus and characterize their function. Two cDNA clones encoding the Salp16-like sequences were obtained from the salivary glands of fed female I. persulcatus ticks and designated Salp16 Iper1 and Iper2. Gene expression analyses showed that the Salp16 Iper genes were expressed specifically in the salivary glands and were up-regulated by blood feeding. These proteins attenuated the oxidative burst of activated bovine neutrophils and inhibited their migration induced by the chemoattractant interleukin-8 (IL-8). These results demonstrate that Salp16 Iper proteins contribute to the establishment of blood feeding as an immunosuppressant of neutrophil, an essential factor in innate host immunity. Further examination of the role of Salp16 Iper in the transmission of pathogens, including A. phagocytophilum, will increase our understanding of the tick-host-pathogen interface.
Salp16是一种16千道尔顿的蜱唾液腺蛋白，已知它是嗜吞噬细胞无形体（一种引起人畜共患无形体病的专性细胞内病原体）从其哺乳动物宿主传播至肩突硬蜱的相关分子。最近，在日本发现了嗜吞噬细胞无形体的存在，全沟硬蜱被确定为其传播媒介之一。本研究的目的是鉴定全沟硬蜱中的Salp16基因并表征其功能。从饱血雌性全沟硬蜱的唾液腺中获得了两个编码Salp16样序列的cDNA克隆，分别命名为Salp16 Iper1和Iper2。基因表达分析表明，Salp16 Iper基因在唾液腺中特异性表达，并在吸血后上调。这些蛋白质减弱了活化的牛中性粒细胞的氧化爆发，并抑制了趋化因子白细胞介素-8（IL-8）诱导的它们的迁移。这些结果表明，Salp16 Iper蛋白作为中性粒细胞的免疫抑制剂，有助于建立吸血过程，而中性粒细胞是宿主固有免疫的重要因素。进一步研究Salp16 Iper在包括嗜吞噬细胞无形体在内的病原体传播中的作用，将增进我们对蜱-宿主-病原体界面的理解。
