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为了比较国内不同猪繁殖与呼吸综合征(porcine reproductive and respiratory syndrome,PRRS)弱毒疫苗的安全性和有效性,本研究将17头PRRSV抗原和抗体双阴性的28日龄仔猪随机分为4组,TJM-F92株弱毒疫苗组,JXA1-R株弱毒疫苗组,经典株弱毒疫苗(VR2332来源)组和注射生理盐水对照组。免疫后7,14,21,28d分别采血,ELISA抗体检测试剂盒检测PRRSV抗体,结果从免疫后14d起PRRSV抗体开始转阳,但各试验组的抗体水平无明显差异。对免疫后14d所采血样进行病毒分离,TJM-F92株免疫组未分离到PRRSV疫苗毒,JXA1-R株免疫组2头猪分离到PRRSV疫苗毒,经典株免疫组只1头猪分离到PRRSV疫苗毒。免疫后28d,所有猪接种PRRSV强毒株TJ株进行攻毒试验,观察各组猪的体温、临床症状;攻毒后21d,所有猪安乐死,剖检观察肺部病理变化。结果显示,TJM-F92株和JXA1-R株免疫组均未出现临床发病猪,经典株免疫组2头猪出现临床发病,对照组全部临床发病,死亡1头。经典株免疫组临床发病猪出现典型PRRSV感染肺部病理变化,而TJM-F92株和JXA1-R株免疫组均未发现典型PRRSV感染肺部病理变化。本研究证实TJM-F92株和JXA1-R株对高致病性PRRSV的免疫效果优于经典株弱毒疫苗,TJM-F92疫苗株与JXA1-R疫苗株相比,疫苗毒在体内带毒时间更短,安全性更高。
In order to compare the safety and efficacy of different attenuated PRRS vaccines in domestic piglets, 17 PRRSV and 28-day-old piglets with negative antibody were randomly divided into 4 groups, TJM-F92 attenuated vaccine group, JXA1-R attenuated vaccine group, classical attenuated vaccine strain (VR2332 source) group and injected normal saline control group. Blood samples were collected at 7, 14, 21 and 28 days after immunization. The ELISA kit was used to detect PRRSV antibody. PRRSV antibody began to turn positive 14 days after immunization. However, there was no significant difference between the two groups. PRRSV vaccine was not isolated from the TJM-F92 strain, and PRRSV vaccine strain was isolated from 2 pigs from the JXA1-R strain immune group. Only 1 pig from the classical strain immunized group was isolated from PRRSV Vaccine poison. All pigs were challenged with TPR strain of PRRSV 28 days after immunization to observe the body temperature and clinical symptoms of pigs. All pigs were euthanized 21 days after challenge, and pathological changes of the lungs were observed by autopsy. The results showed that there were no clinical onset pigs in the immunized groups of TJM-F92 and JXA1-R strains, and 2 pigs in the classical strain immunized group had clinical symptoms. All the clinical cases in the control group were killed and 1 died. Pathological changes of the lungs were observed in the PRRSV-infected pigs in the classical strain immunized group, but not in the TJM-F92 and JXA1-R strains. This study confirmed that the TJM-F92 strain and the JXA1-R strain were superior to the classical attenuated vaccine against the highly pathogenic PRRSV vaccine. Compared with the JXA1-R vaccine strain, the TJM-F92 vaccine strain had a higher virulence in vivo Short, more secure.