高致病性猪繁殖与呼吸综合征病毒HBR变异株第125代的毒力试验  

Virulence test of a highly pathogenic HBR 125 mutant strain of porcine reproductive and respiratory syndrome virus

作　　者：危艳武[1] 刘长明[1] 范培虎[1] 吴洪丽[1] 温士刚[1] 

机构地区：[1]中国农业科学院哈尔滨兽医研究所兽医生物技术国家重点实验室猪传染病研究室,黑龙江哈尔滨150001

出　　处：《中国兽医科学》2011年第2期152-158,共7页Chinese Veterinary Science

基　　金：国家自然科学基金资助项目(30871859);中央级公益性科研院所基本科研业务费(2010-054)

摘　　要：从临床病例中分离到1株高致病性猪繁殖与呼吸综合征病毒(PRRSV)变异株HBR,经细胞传代和蚀斑克隆获得了1株增殖性能稳定的传代毒株。为了检测该毒株在Marc-145细胞传代过程中毒力的变化,用PRRSV-HBR株第125代培养物(毒价为107.5 TCID50/mL)经肌肉注射和滴鼻途径接种18头35日龄PRRSV抗体阴性猪,同时设未接种对照组。结果试验猪未出现明显的临床症状。用RT-PCR法检测试验猪血清,从第3天开始出现阳性,第7～14天达到高峰,第28天后转为阴性。对同一时间迫杀的试验猪检测各脏器组织中的病毒抗原分布情况,结果表明,感染后第7～14天试验猪多数脏器呈阳性反应,第21～42天病毒集中在脾、腹股沟淋巴结、颌下淋巴结等组织。病理学观察发现,第7～14天试验猪淋巴结及肺出现轻度病变。动物感染试验表明,尽管试验猪未显示明显的临床症状,但从病毒血症、病毒体内分布、病理变化等方面看,该毒株仍然具有一定的毒力,用于弱毒疫苗的研制还有待进一步驯化致弱。A highly pathogenic mutant strain（HBR） of porcine reproductive and respiratory syndrome virus（PRRSV） was isolated from clinical cases.Through viral passage in cell culture and plaque purification,a replication-stable strain was obtained.To examine the changes in virulence during the process of cell culture passage,the 125th generation of PRRSV-HBR culture at a titer of 107.5 TCID50/mL was used to inoculate eighteen 35-day-old pigs with PRRSV antibody negative by means of intramuscular injection and intranasal inoculation.Mock infected group was set up simultaneously for comparison.After viral inoculation,infected pigs did not show clinical symptoms such as obvious increases in body temperature,loss of appetite,listlessness,weight loss,eyelid swelling,or swollen superficial lymph nodes.Viremia was tested by RT-PCR.Positives appeared on day 3 and peaked on days 7 to 14,returning to negative after 28 days.Pigs were sacrificed at regular intervals to examine viral antigens in different organs.The results indicated that most organs taken from the infected pigs showed positive reactions after 1 to 2 weeks.After 3 to 6 weeks,the virus was concentrated in tissues such as the spleen,inguinal lymph nodes,and submandibular lymph nodes.Pathological examination showed that the lymph nodes and lungs of the infected pigs contained mild lesions on week 1 to 2 post-infection.The infectivity assays indicated that although the 125th generation of PRRSV-HBR cultured virus did not exhibit visible clinical symptoms,it still clearly possessed virulence demonstrated by viremia testing,viral distribution within the body,and pathological changes.Further attenuation is needed for the development of live vaccine.

关 键 词：猪繁殖与呼吸综合征病毒 变异毒株 细胞传代 毒力试验 

分 类 号：S852.659.6[农业科学—基础兽医学]