【作者】 马金玲；

【导师】 王雯慧； ?蒈?；

【作者基本信息】 甘肃农业大学 ， 基础兽医学， 2003， 硕士

【摘要】 在国内首次用全序列已知的原始毒株Akesu／58通过舌面穿刺感染牦牛，建立了FMDV持续感染动物模型，定期刮取食道／咽部(Oesophageal-Pharyngeal，O／P)黏液、采集血清，并跟踪检测了12个月，同时采用反转录—聚合酶链反应(RT-PCR)、分子克隆和核酸序列测定技术对其中阳性样品的VP1、L、3ABC基因进行了序列测定，通过计算机软件对序列进行比较分析，绘制系统发生树。结果表明，所感染的5头牦牛均持续带毒，只是由于个体差异，带毒的时间长短不一。在测定的持续感染毒株中，VP1、L、3ABC基因发生了不同程度的变异，其中VP1变异最大，并且细胞受体结合位点由原始毒株的SGD变为了RGD，这可能是发生了适应性突变。对于不同的个体，3ABC特别3A基因变化较大，它的变异有可能造成毒株对宿主适应性的改变。此外，将RT-PCR检测结果与血清中非结构蛋白抗体的检测结果相比较，发现非结构蛋白抗体水平较高的个体，持续带毒的可能性也越大，但两者之间没有线性化关系。更多还原

【Abstract】 This is the first time in our country to construct animal model of FMDV persistent infection, five yaks were infected with the oringinal strain Akesu/58 that the full-length genome has known by puncturing in the tongue, then Oesophageal-Pharyngeal(O/P) fluid and serum were collected and detected, lasting 12 months. Towards the positive samples, by RT-PCR, molecular cloning, sequencing and biologic software, VP1, L and 3ABC genes sequences were achieved and analyzed. The results showed that the five infected yaks were in carrier state, but persistent time was various because of individual difference among them. VP1, L and 3 ABC genes of persistence strains had incoordinate variation and VP1 gene was the most evident. The central tripeptide of binding cell receptor in these strains was Arg-Gly-Asp(RGD) instead of Ser-Gly-Asp(SGD) in oringinal strain. This may be the result of adaptive mutation. As for different hosts, 3 ABC, especially 3 A gene, varied obviously and its variation contributed to the changes in the hosts of virus. In addition, the comparison of the result of RT-RCR and non-structural (NS) protein antibody in serum showed that the higher NS protein antibody was, the more possible persistent infection was, but there was not linear relationship between them.更多还原