Analysis of molecular escape mechanism of Theileria

泰勒虫分子逃逸机制分析

基本信息

批准号：
05454115
负责人：
ONUMA Misao
金额：
$ 4.22万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

Cattle in Japan have been found to be infected with Theileria sergenti. Antigenic polymorphism has been demonstrated among stocks or field isolates of T.sergenti by using monoclonal antibodies. The results of Southern blot hybridization have also shown the genomic diversity of T.sergenti isolates.As one of the mechanisms that the parasitic protozoa evade host immune responses, they are known to express surface molecules with variant antigenic forms. This antigenic variation is related to change at genomic level, point mutatation, deletion or gene rearrangement in malaria and trypanosomes.To understand the evasion mechanism of T.sergenti, we analyzed one of the major surface proteins of merozoites (p32). We isolated 3 clones from cDNA library and nucleotide sequences were determined. Comparison of nucleotide sequences reveals at least 3 genetically different parasite population may coexist, and that transition of predominant parasite populations might occur during persistent infection. We further analyzed p32 antigenic difference of parasites obtained from different parasitemia peaks. Antigenic differences were observed among parasites from different peaks during persistent infection.There is a good correlation between the genotype changes and antibody responses. Population change in vivo indicates one of the parasite evasion mechanisms from host immune responses, because genetically different population may express antigenically different surface molecules.

已经发现日本的牛被塞林蒂感染。通过使用单克隆抗体，已经证明了T.sergenti的库存或田间分离株之间的抗原性多态性。 Southern印迹杂交的结果还显示了T.sergenti分离株的基因组多样性。作为寄生虫原生动物逃避宿主免疫反应的一种机制，它们被称为具有变异抗原性形式的表面分子。这种抗原变异与疟疾和锥虫的基因组水平，点突变，缺失或基因重排的变化有关。为了了解T.Serergenti的逃避机制，我们分析了Merozoites的主要表面蛋白之一（p32）。我们从cDNA文库中分离了3个克隆，并确定了核苷酸序列。核苷酸序列的比较揭示了至少3个遗传上不同的寄生虫种群可能并存，并且在持续感染期间可能会发生主要的寄生虫种群的过渡。我们进一步分析了从不同寄生虫峰获得的寄生虫的p32抗原差异。在持续感染期间，来自不同峰的寄生虫之间观察到抗原差异。基因型变化与抗体反应之间存在良好的相关性。人口变化体内表明宿主免疫反应的寄生虫逃避机制之一，因为遗传上不同的人群可能表达抗原上不同的表面分子。