Developments of Anti-tick Vaccine and Bio-acaricides Using Recombinant Virus of Tick Bioactive Molecules

这项研究的目的是开发不会对环境和健康造成与化学残留相关的风险并可用作化学杀虫剂的有吸引力的替代化学杀虫剂的生物杀螨剂和/或新型滴虫疫苗。为了实现这一途径，我们必须弄清硬蜱中负责吸血和天然免疫的生物活性分子，并确定为生物杀螨剂和/或疫苗候选，因为吸血和天然免疫是硬蜱生存、繁殖和病原体传播所必需的重要特征。因此，对这些生物膜的生化和功能分析可能是一种有趣的靶标分子，可以为新型和环境安全的硬蜱防治提供新的靶标。(1)在本项目期间，我们可以开展大约50种新的长角血蜱生物膜的分子鉴定和特性研究。(2)我们测试了表达长角血蜱几丁质酶基因的重组杆状病毒对硬蜱生物杀螨剂的效果。重组病毒和几丁质酶的混合物比单纯的几丁质酶和重组病毒更快地杀死硬蜱。(3)我们检测了两种重组水泥样蛋白hlim2和hlim3对小鼠的疫苗效果。Hlim2和hlim3对硬蜱吞噬体重和粘附性的互补作用表明这两种重组蛋白适合用于鸡尾酒疫苗。(4)我们用来自硬蜱的富含甘氨酸的蛋白RH50免疫兔子，并对其疫苗的免疫效果进行了评估。结果表明，RH50蛋白在成虫和若虫体内的粘附率较低，而以重组RH50免疫的兔为食的若虫死亡率较高，因此RH50蛋白可作为抗蚤疫苗的候选蛋白。

The objective of this research is to develop bioacaricides and /or novel vaccines for tick control that do not pose environmental and health risks associated with chemical residues and can be used as an attractive alternative to chemical pesticides. In order to realize this approach, we must clarify tick bioactive molecules (TBMs) that are responsible for the blood-sucking and innate immunity in ticks and identify as the bioacaricide and/or vaccine candidates, because blood-sucking and innate immunity are important features of the hard ticks essential for survival, reproduction and pathogen transmission. Biochemical and functional analysis of these TBMs may therefore represent interesting target molecules to which novel and environmentally safety tick control could be directed.(1) During the period of this project, we could carry out about 50 novel TBMs the molecular identification and characterization researches on about 50 novel TBMs of the ixodid tick, Haemaphysalis longicornis.(2) We have tested a recombinant baculovirus expressing a chitinase gene from H. longicornis for its efficacy as a tick bioacaricide. A mixture of recombinant virus and chitinase was found to kill ticks faster than pure chitinase and recombinant virus alone.(3) We have examined the vaccine efficacy of two recombinant cement-like proteins, hlim2 and hlim3 against mice. The complementary effects of hlim2 on tick engorged body weight and hlim3 on tick attachment indicate the suitability of the 2 recombinant proteins for use in a cocktail vaccine.(4) We have immunized rabbits with a glycine-rich protein, RH50, from the tick Rhipicephalus haemaphysaloides and evaluated its vaccine potential against tick feeding. The results showed that the RH50 protein could be useful candidate for anti-tick vaccine because the low attachment rate both in the adult and nymphal ticks, and the high mortality of nymphal ticks feeding on recombinant RH50 immunized rabbits were found.