Wang Fangfang, Lu Xiaojuan, Guo Fengxun, Gong Haiyan, Zhang Houshuang, Zhou Yongzhi, Cao Jie, Zhou Jinlin
Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
Vet Parasitol. 2017 Jun 15;240:49-59. doi: 10.1016/j.vetpar.2017.03.017. Epub 2017 Mar 23.
An immunomodulatory protein designated RH36 was identified in the tick Rhipicephalus haemaphysaloides. The cDNA sequence of RH36 has 844bp and encodes a deduced protein with a predicted molecular weight of 24kDa. Bioinformatics analysis indicated that RH36 presented a degree of similarity of 34.36% with the immunomodulatory protein p36 from the tick Dermacentor andersoni. The recombinant RH36 (rRH36) expressed in Sf9 insect cells suppressed the T-lymphocyte mitogen-driven in vitro proliferation of splenocytes and the expression of several cytokines such as IL-2, IL-12, and TNF-α. Furthermore, the proliferation of splenocytes isolated from rRH36-inoculated mice was significantly lower than that in control mice, suggesting that rRH36 could directly suppress immune responses in vivo. In addition, microarray analysis of splenocytes indicated that the expression of several immunomodulatory genes was downregulated by rRH36. The silencing of the RH36 gene by RNAi led to a 37.5% decrease in the tick attachment rate 24h after placement into the rabbit ears, whereas vaccination with RH36 caused a 53.06% decrease in the tick engorgement rate. Unexpectedly, RNAi induced a significant decrease in the oviposition rate, ovary weight at day 12 after engorgement, and egg-hatching rate. The effects of RH36 on blood feeding and oviposition were further confirmed by vaccination tests using the recombinant protein. These results indicate that RH36 is a novel member of immunosuppressant proteins and affects tick blood feeding and oviposition.
在血红扇头蜱中鉴定出一种名为RH36的免疫调节蛋白。RH36的cDNA序列有844bp，编码一种推导蛋白，预测分子量为24kDa。生物信息学分析表明，RH36与来自安德森革蜱的免疫调节蛋白p36有34.36%的相似度。在Sf9昆虫细胞中表达的重组RH36（rRH36）抑制了T淋巴细胞有丝分裂原驱动的脾细胞体外增殖以及几种细胞因子如IL-2、IL-12和TNF-α的表达。此外，从接种rRH36的小鼠分离的脾细胞增殖明显低于对照小鼠，这表明rRH36可直接抑制体内免疫反应。此外，对脾细胞的微阵列分析表明，几种免疫调节基因的表达被rRH36下调。通过RNA干扰使RH36基因沉默导致蜱虫放置在兔耳中24小时后的附着率降低37.5%，而用RH36疫苗接种导致蜱虫饱血率降低53.06%。出乎意料的是，RNA干扰导致产卵率、饱血后第12天的卵巢重量和卵孵化率显著下降。使用重组蛋白的疫苗接种试验进一步证实了RH36对吸血和产卵的影响。这些结果表明，RH36是免疫抑制蛋白的一个新成员，并影响蜱虫的吸血和产卵。
