Effects of low (modified-live virus vaccine) and high (VR-2385)-virulence strains of porcine reproductive and respiratory syndrome virus on pulmonary clearance of copper particles in pigs
Effects of low (modified-live virus vaccine) and high (VR-2385)-virulence strains of porcine reproductive and respiratory syndrome virus on pulmonary clearance of copper particles in pigs
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DOI：
10.1177/030098589803500509
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发表时间：
1998-09-01
影响因子：
2.4
通讯作者：
Royer, RL
中科院分区：
文献类型：
--
作者：
Thanawongnuwech, R;Halbur, PG;Royer, RL
将来自无猪繁殖与呼吸综合征病毒（PRSSV）的猪群的75头3周龄杂交猪随机分配至3组：未感染对照组、鼻内接种RespPRRS/Repro（TM）改良活病毒疫苗（RespPRRS）的猪和鼻内接种PRRSV高毒力毒株（VR-2385）的猪。在猪接种PRRSV后3、7、10、14或28天（DPI）进行尸检前30分钟，将3%酞菁铜四硫酸（0.2 ml/kg）在生理盐水中静脉输注。输注后0、15或30分钟采集的样本中血清铜浓度无差异。在7、10和14 DPI时，接种VR-2385的猪的肺中的铜浓度显著低于对照和接种RespPRRS的猪的肺中的水平（P < 0.05）。在10 DPI时观察到组间的最大差异。肝脏和脾脏铜浓度略高，但不显着，在两个PRRSV感染组。RespPRRS接种组中受肉眼可见肺炎影响的肺部百分比范围为0 - 5.6%，VR-2385接种组为15.2 - 46.4%，病变分别在7和10 DPI时达到峰值。免疫组化结果显示，在肺泡巨噬细胞（PAM）和肺血管内巨噬细胞（PIM）中均存在PRRSV抗原。通过光学显微镜证实了PIM中的铜颗粒。从3至28 DPI的VR-2385感染的猪的支气管肺泡灌洗液和7至28 DPI的RespPRRS接种的猪分离PRRSV。在对照组中未检测到PRRSV、PRRSV抗体或PRRSV诱导的肺炎。这些结果表明：1）PRRSV对PIM摄取铜颗粒具有不利影响，2）PRRSV诱导的PIM损伤的严重程度在毒株之间不同，3）PRRSV诱导的肺清除率降低的证明支持了PRRSV感染可能使猪更容易患细菌性败血症的假设。
Seventy-five 3-week-old, crossbred pigs from a herd free of porcine reproductive and respiratory syndrome virus (PRSSV) were randomly assigned to three groups: uninfected controls, pigs inoculated intranasally with RespPRRS/Repro(TM) modified-live virus vaccine (RespPRRS), and pigs inoculated intranasally with a high-virulence strain of PRRSV (VR-2385). Pigs were intravenously infused with 3% copper phthalocyanine tetrasulfonic acid (0.2 ml/kg) in normal saline 30 minutes before necropsy, which was performed 3, 7, 10, 14, or 28 days postinoculation (DPI) with PRRSV. There were no differences in serum copper concentration in samples collected at 0, 15, or 30 minutes after infusion. Copper concentrations in the lungs of VR-2385-inoculated pigs were significantly lower than levels in the lungs of control and RespPRRS-inoculated pigs at 7, 10, and 14 DPI (P < 0.05). The greatest difference between the groups was observed at 10 DPI. Liver and spleen copper concentrations were slightly, but not significantly, higher in both PRRSV-infected groups. The percentage of lung affected by grossly visible pneumonia ranged from 0 to 5.6% in the RespPRRS-inoculated group and from 15.2 to 46.4% in the VR-2385-inoculated group, with lesions peaking at 7 and 10 DPI, respectively. PRRSV antigen was demonstrated in both pulmonary alveolar macrophages (PAMs) and pulmonary intravascular macrophages (PIMs) by immunohistochemical methods. Copper particles were demonstrated in the PIMs by light microscopy. PRRSV was isolated from bronchoalveolar lavage fluid of VR-2385-infected pigs from 3 to 28 DPI and from RespPRRS-inoculated pigs from 7 to 28 DPI. No PRRSV, PRRSV antibodies, or PRRSV-induced pneumonia was detected in the control group. These results suggest chat 1) PRRSV has a detrimental effect on the: uptake of copper particles by PIMs, 2) the severity of PRRSV-induced damage to PIMs differs among strains, and 3) demonstration of PRRSV-induced decreased pulmonary clearance supports the hypothesis that PRRSV infection may make pigs more susceptible to bacterial septicemia.