Molecular escape mechanisms of Theileria parasites

泰勒虫寄生虫的分子逃逸机制

• 批准号: 07406019
• 负责人: ONUMA Misao
• 金额: $ 7.94万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07406019/
• 关键词: Theileria parasites; piroplasm; evasion mechanism; parasite genotype; tick; 原虫表面抗原遺伝子; ダニ体内の有性生殖; 持続感染; 抗原多型性; バキュロウィルス発現系; 表面抗原; PCR

Theileria sergenti is a tick-borne protozoa of cattle. T.sergenti infected calves show persistent infection, possibly over their life span, but the mechanisms by which the parasites evade host defense mechanisms are not clearly understood. The complete life-cycle of T.sergenti in the mammalian host and tick vector remains unclear, the parasite may undergo a sexual stage in tick gut. To study the population changes during persistent infection in cattle and vector ticks, we have inoculated T.sergenti which consist of 2 parasite populations with C and I type allele of p32 and analyzed the population changes by allele-specific PCR to differentiate between individual types of parasites. Changes in a dominant parasite population were demonstrated during transmission from calves to the tick vector and from infected ticks to calves. The antigenic diversity which may be produced at the sexual stage in tick vector. The analysis of chromosome provide us the basic information to study the generation of genetic and antigenic polymorphism.Chromosome analysis of T.sergenti showed 4 chromosomes. From the results of Southern blot analysis, p32 gene was located on the 1st chromosome, p23, heat shock protein 70 (HSP 70) and cystein proteinase genes were on the chromosome 2 and ribosomal RNA gene was on chromosomes 1 and 3/4.

瑟氏泰勒虫是一种蜱传的牛原虫。瑟氏锥虫感染的小牛表现出持续感染，可能在其整个生命周期内，但寄生虫逃避宿主防御机制的机制尚不清楚。瑟氏锥虫在哺乳动物宿主和蜱媒介中的完整生活史尚不清楚，寄生虫可能在蜱肠道中经历有性阶段。为了研究牛和媒介蜱持续感染过程中的种群变化，我们用p32的C型和I型等位基因接种了由2个寄生虫种群组成的瑟氏锥虫，并通过等位基因特异性PCR分析了种群变化，以区分不同类型的寄生虫。在从小牛传播到蜱虫媒介以及从受感染的蜱虫传播到小牛的过程中，证明了主要寄生虫种群的变化。蜱媒在有性阶段可能产生的抗原多样性。染色体分析为研究瑟氏锥虫的遗传和抗原多态性的产生提供了基础资料。Southern杂交结果表明，p32基因位于第1号染色体上，p23、热休克蛋白70（HSP 70）和半胱氨酸蛋白酶基因位于第2号染色体上，核糖体RNA基因位于第1号和第3/4号染色体上。

项目成果

Watarai S., et al.: "Isolaton and characterization of gangliosides from T. sergenti." J.Vet.Med.Sci.58. 1099-1105 (1996)

Watarai S. 等人：“T. sergenti 神经节苷脂的分离和表征”。

Sako, Y.: "Expression of major piroplasm surface protein of Theileria sergenti in sporozoite stage." J.Vet.Med.Sci.in press. (1999)

Sako，Y.：“谢氏泰勒虫在子孢子阶段主要梨质表面蛋白的表达。”

Kawazu, S.: "Phylogenetic relationships of the benign Theileria species in cattle and Asian buffalo based on the major piroplasm surface protein (p33-34) gene sequence." Int.J.Parasiol.(in press). (1999)

Kawazu, S.：“基于主要梨质表面蛋白 (p33-34) 基因序列的牛和亚洲水牛良性泰勒虫物种的系统发育关系。”

Onuma M.: "Theileria parasite infection in East Asia and control of the disease." Comp.Immun.Microbiol.Infect.Dis.(in press). (1998)

Onuma M.：“东亚泰勒虫寄生虫感染及疾病控制。”

Sako Y.: "Molecular cloning and characterization of 23kDa piroplasm surface proteins of Theileria sergenti and T.buffeli." Int.J.Parasitol.(in press). (1999)

Sako Y.：“谢氏泰勒虫和布氏泰勒虫 23kDa 梨质表面蛋白的分子克隆和表征。”