PCV2疫苗免疫效果评价及分离株基因遗传变异分析

发布时间：2018-05-07 22:28

本文选题：猪圆环病毒2型 + 抗体检测　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：猪圆环病毒2型(PCV2)在猪群中感染率较高,除了本身可以引起猪发病外可还会造成免疫系统损害,引起多种疾病的发生。疫苗免疫接种可以减少PCV2对免疫猪的危害程度、组织中病毒的载量,也为猪场进行PCV2的净化提供了基础条件。疫苗免疫后的抗体水平是评价其效果的主要指标,对免疫猪体内PCV2病毒的检测是评价疫苗效果的最直接指标。在专业实习期间,主要从事PCV2疫苗免疫效果的评价,先后采集了7个长期坚持进行PCV2的猪场猪血清,2个未进行PCV2疫苗免疫猪场的血清样品,对其血清抗体和病毒进行检测,以期从抗体水平和病毒清除方面说明疫苗免疫在猪圆环病毒病防控中的作用。在分析疫苗免疫和病毒感染关系的基础上,本研究又将检测为PCV2核酸阳性的样品中克隆了其rep和cap基因,进行序遗传变异分析,以期从核酸水平上分析PCV2感染的原因,也为疫苗研制提供基础资料。本研究获得以下结果:(1)从来自7个PCV2疫苗免疫猪场的178份血清中抗体阳性率65.17%(116/178),最高抗体阳性率达到90.20%,最低仅有26.67%;2个非PCV2疫苗免疫猪场的84份样品中抗体阳性率15.48%(13/84)。(2)262份血清样品中6份PCV2核酸阳性,占2.29%(6/262)。在7个疫苗免疫场中有2个场的血清中检出PCV2核酸,阳性率分别为3.33%(1/30)和9.09%(1/11)。非免疫猪场1的阳性率为2.86%(1/35),猪场2为6.12%(3/49)。(3)PCV2核酸阳性的样品其特异性抗体均为阴性。(4)6个分离株的rep基因序列的同源性较高,为97.3%~99.8%;GS1、3、4的同源性较高,GS2、5、6同源性较高,GS1、3、4与GS2、5、6的同源性较低。(5)6个分离株之间以及与国内外分离株之间均存在一些基因差异,分离株的cap基因之间同源性最高为98.1%,最低为87.7%;在进化树上同属于一个大的分支,和国内分离的PCV2d基因亚型的毒株存在较高的同源性。
[Abstract]:The infection rate of porcine circovirus type 2 (PCV2) is higher in pigs, which can cause immune system damage and cause many diseases. Vaccination can reduce the harm of PCV2 to immunized pigs and the viral load in the tissues. It also provides the basic conditions for the purification of PCV2 in pig farms. The level of antibody after immunization is the main index to evaluate the effect of the vaccine, and the detection of PCV2 virus in immunized pigs is the most direct index to evaluate the effect of vaccine. During the period of professional practice, he was mainly engaged in the evaluation of the immune effect of PCV2 vaccine. Seven pig serum samples which persisted in PCV2 for a long period of time, and two serum samples from pig farm without PCV2 vaccine immunization were collected, and their serum antibodies and viruses were detected. In order to explain the role of vaccine immunization in prevention and control of porcine circovirus disease from antibody level and virus clearance. Based on the analysis of the relationship between vaccine immunization and viral infection, the rep and cap genes were cloned from the samples positive for PCV2 nucleic acid, and the sequence genetic variation analysis was carried out in order to analyze the causes of PCV2 infection at nucleic acid level. It also provides basic information for vaccine development. The results of this study were as follows: 1) the antibody positive rate of 178 sera from seven PCV2 vaccine vaccination farms was 65.17 / 116 / 178. The highest antibody positive rate was 90.20 and the lowest was 26.67. The antibody positive rate of 84 samples from two non-PCV2 vaccine vaccination farms was 15.48% 13 / 84 .2262%. Six of the serum samples were PCV2 nucleic acid positive. 2.29 / 262a. PCV2 nucleic acid was detected in 2 of the 7 vaccine immunization fields, the positive rates were 3.33 / 30) and 9.09% / 11 ~ (-1 / 11), respectively.The positive rate of PCV2 nucleic acid was 3.33% and 9.09% / 11%, respectively. The positive rate of non-immunized pig farm 1 was 2.86 / 35. The rep gene sequence of the six isolates were highly homologous to each other in the samples with 6.12%(3/49).(3)PCV2 nucleic acid positive and the specific antibodies were all negative. There were some genetic differences among the six isolates, and between the six isolates and the domestic and foreign isolates. The highest homology of cap gene was 98.1 and the lowest was 87.7. The cap gene belonged to a large branch in the evolutionary tree and had high homology with the domestic isolates of PCV2d gene subtype.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S858.28

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