Biological responses to porcine respiratory and reproductive syndrome virus in pigs of two genetic populations.
Biological responses to porcine respiratory and reproductive syndrome virus in pigs of two genetic populations.
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两个遗传群体的猪对猪呼吸与繁殖综合征病毒的生物反应。
DOI：
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发表时间：
2005
影响因子：
3.3
通讯作者：
Rodger K. Johnson
中科院分区：
文献类型：
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作者：
D. Petry;J. Holl;John S. Weber;A. Doster;F. A. Osorio;Rodger K. Johnson
选用东北指标系(NEI)猪100头和汉普夏-杜洛克杂交猪(HD)各100头，于26日龄经鼻接种猪呼吸与繁殖综合征病毒(PRRSV 97-7895株)，以确定猪对PRRSV的应答是否存在遗传变异。每头感染猪的一窝未受感染的仔猪作为对照。猪来自163个水坝和83头公猪。记录体重和直肠温度，并在接种前d0和接种后d4、7、14d采集血样。于第14天处死猪，收集肺和支气管淋巴结，置于适宜切割温度的复合液中，在-80℃冷冻，通过细胞培养分离确定血清、肺组织和支气管淋巴结中PRRSV的存在。第14天采集的血清中抗体的存在通过商业酶联免疫吸附试验来确定。对肺组织进行显微镜检查，并对病变的发生率和严重程度进行评分(1~3分；1=无病变或很少病变，3=严重间质性肺炎)。数据采用混合模型进行分析，该模型包含了随机的父系效应和大坝效应。X线处理对体重变化和直肠温度的互作显著(P<；0.001)。未感染HD猪0~14d体重增加0.67 kg，直肠温度平均升高0.32℃(P<；0.001)，而感染HD猪增重0.34 kg，体温降低-0.54℃(P<；0.001)。病毒滴度(细胞培养感染量50%/毫升)在第4天(10(4.52)vs 10(4.22))、7(10(4.47)vs 10(3.99)、14(10(3.49)vs 10(3.23))时HD高于NEI(P<；0.05)。HD猪肺(P=0.11)和支气管淋巴结(P=0.07)的病毒滴度均高于NEI猪。感染猪的抗体信号与阳性(S/P)的ELISA值在0.18~3.38之间，88%的猪的抗体水平为~gt；或=0.40，这是本试验的阳性阈值。未感染猪的S/P范围为0~1.11，99%的猪有水平或=0.40。HD组感染猪的S/P值平均比NEI组高0.23个单位(P<；0.001)。HD猪的间质性肺炎发生率和平均病变评分均高于NEI猪(P<；0.001)。综上所述，这两个品系的猪对感染PRRSV的反应不同，表明存在潜在的遗传变异。
One hundred pigs from the NE Index Line (NEI) and 100 Hampshire-Duroc cross pigs (HD) were inoculated intranasally with porcine respiratory and reproductive syndrome virus (PRRSV 97-7895 strain) at 26 d of age to determine whether genetic variation in response to PRRSV exists. An uninfected littermate to each infected pig served as a control. Pigs were from 163 dams and 83 sires. Body weight and rectal temperature were recorded, and blood samples were drawn from each pig on d 0 before inoculation and on d 4, 7, and 14 after inoculation. Pigs were sacrificed on d 14. Lung and bronchial lymph nodes were collected, placed in optimal cutting temperature compound, and frozen at -80 degrees C. The presence of PRRSV in serum and in lung tissue and bronchial lymph nodes was determined by isolation in cell culture. The presence of antibodies in serum collected on d 14 was determined by a commercial ELISA test. Lung tissue was examined microscopically and scored for incidence and severity of lesions (score of 1 to 3; 1 = no or few lesions, and 3 = severe interstitial pneumonia). Data were analyzed with a mixed model that included random sire and dam effects. The interaction of line x treatment was significant (P < 0.001) for weight change and rectal temperature. Un-infected HD pigs gained 0.67 kg more from d 0 to 14 and averaged 0.32 degrees C higher rectal temperature than uninfected NEI pigs (P < 0.001), whereas infected NEI pigs gained 0.34 kg more and had -0.54 degrees C lower temperature than infected HD pigs (P < 0.001). Viremic titer (cell culture infectious dose 50%/mL) was greater (P < 0.05) in HD than NEI at d 4 (10(4.52) vs. 10(4.22)), 7 (10(4.47) vs. 10(3.99)), and 14 (10(3.49) vs. 10(3.23)). Viral titer loads in lung (P = 0.11) and bronchial lymph nodes tended (P = 0.07) to be greater in HD than NEI pigs. Antibody signal-to-positive (S/P) ELISA ratios in infected pigs ranged from 0.18 to 3.38, and 88% had levels > or = 0.40, which is the positive threshold for this ELISA. The S/P range in uninfected pigs was 0 to 1.11, and 99% had levels < or = 0.40. Mean S/P ratio for infected pigs was 0.23 units higher in HD than in NEI (P < 0.001). The HD pigs had a greater incidence of interstitial pneumonia and 0.65 higher mean lesion scores than NEI pigs (P < 0.001). In summary, responses of pigs of the two lines to infection with PRRSV differed, indicating that underlying genetic variation existed.