Antibody response and maternal immunity upon boosting PRRSV-immune sows with experimental farm-specific and commercial PRRSV vaccines
Antibody response and maternal immunity upon boosting PRRSV-immune sows with experimental farm-specific and commercial PRRSV vaccines
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DOI：
10.1016/j.vetmic.2013.08.017
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发表时间：
2013-12-27
影响因子：
3.3
通讯作者：
Nauwynck, Hans J.
中科院分区：
文献类型：
--
作者：
Geldhof, Marc F.;Van Breedam, Wander;Nauwynck, Hans J.
猪繁殖与呼吸综合征病毒(PRRSV)可引起母猪繁殖障碍和各年龄段猪的呼吸系统疾病。尽管经常使用疫苗来维持母猪的PRRSV免疫力，但目前使用的疫苗如何影响对PRRSV免疫母猪对当前流行的和遗传上不同的PRRSV变异体的免疫力，即由于以前感染或接种过PRRSV病毒而具有PRRSV特异性免疫力的母猪，人们知之甚少。因此，本研究旨在评估市场上可获得的减毒/灭活PRRSV疫苗和自体灭活PRRSV疫苗的能力，以提高PRRSV免疫母猪对当前流行的PRRSV变异株的抗体免疫力。PRRSV分离株来自3个出现PRRSV相关问题的不同猪群，尽管定期接种了对母猪和母猪的疫苗。在研究的第一部分，评估了3个猪群中PRRSV免疫的非妊娠替代母猪在商业PRRSV疫苗和灭活农场特异性PRRSV疫苗加强免疫后的PRRSV特异性抗体反应。在接种了相应的农场特定灭活疫苗的所有母猪组中，观察到针对农场特定分离株的病毒中和抗体的增加。在来自2个养猪场的母猪中，使用商业减毒Eu型疫苗可以增强针对农场特异性分离株的中和抗体，而使用商业减毒NA型疫苗不会在任何一组母猪中增强农场特异性病毒中和抗体。有趣的是，商业灭活的EU型疫苗增强了来自1个农场的母猪的农场特异性病毒中和抗体。在研究的第二部分，在其中一个农场进行了现场试验，以评估农场专用灭活疫苗和商业减毒欧盟型疫苗对怀孕60天免疫母猪的增强效果。评估了这种疫苗接种对母体免疫和仔猪出生头几周内PRRSV感染模式的影响。在接种农场特异性灭活疫苗后，在所有母猪中检测到农场特异性病毒中和抗体显著增加。病毒中和抗体也通过初乳传递给仔猪，并在这些动物的血清中检测到，直到分娩后5周。相比之下，并不是所有接种了商业减毒疫苗的母猪都显示出农场特异性病毒中和抗体的增加，这组仔猪的病毒中和抗体效价通常较低。有趣的是，两个免疫组的仔猪的病毒感染动物(即血液中带有传染性病毒的动物)的数量都显著低于模拟疫苗接种的仔猪，至少直到产后9周。本研究结果表明，农场专用PRRSV灭活疫苗和商业减毒疫苗可以有效地提高母猪的PRRSV特异性(体液)免疫力，减少断奶仔猪的病毒血症。(C)2013爱思唯尔B.V.保留所有权利。
The porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive failure in sows and respiratory disease in pigs of all ages. Despite the frequent use of vaccines to maintain PRRSV immunity in sows, little is known on how the currently used vaccines affect the immunity against currently circulating and genetically divergent PRRSV variants in PRRSV-immune sows, i.e. sows that have a pre-existing PRRSV-specific immunity due to previous infection with or vaccination against the virus. Therefore, this study aimed to assess the capacity of commercially available attenuated/inactivated PRRSV vaccines and autogenous inactivated PRRSV vaccines - prepared according to a previously optimized in-house protocol - to boost the antibody immunity against currently circulating PRRSV variants in PRRSV-immune sows.PRRSV isolates were obtained from 3 different swine herds experiencing PRRSV-related problems, despite regular vaccination of gilts and sows against the virus. In a first part of the study, the PRRSV-specific antibody response upon booster vaccination with commercial PRRSV vaccines and inactivated farm-specific PRRSV vaccines was evaluated in PRRSVimmune, non-pregnant replacement sows from the 3 herds. A boost in virus-neutralizing antibodies against the farm-specific isolate was observed in all sow groups vaccinated with the corresponding farm-specific inactivated vaccines. Use of the commercial attenuated EU type vaccine boosted neutralizing antibodies against the farm-specific isolate in sows derived from 2 farms, while use of the commercial attenuated NA type vaccine did not boost farm-specific virus-neutralizing antibodies in any of the sow groups. Interestingly, the commercial inactivated EU type vaccine boosted farm-specific virus-neutralizing antibodies in sows from 1 farm. In the second part of the study, a field trial was performed at one of the farms to evaluate the booster effect of an inactivated farm-specific vaccine and a commercial attenuated EU-type vaccine in immune sows at 60 days of gestation. The impact of this vaccination on maternal immunity and on the PRRSV infection pattern in piglets during their first weeks of life was evaluated. Upon vaccination with the farm-specific inactivated vaccine, a significant increase in farm-specific virus-neutralizing antibodies was detected in all sows. Virus-neutralizing antibodies were also transferred to the piglets via colostrum and were detectable in the serum of these animals until 5 weeks after parturition. In contrast, not all sows vaccinated with the commercial attenuated vaccine showed an increase in farm-specific virus-neutralizing antibodies and the piglets of this group generally had lower virusneutralizing antibody titers. Interestingly, the number of viremic animals (i.e. animals that have infectious virus in their bloodstream) was significantly lower among piglets of both vaccinated groups than among piglets of mock-vaccinated sows and this at least until 9 weeks after parturition.The results of this study indicate that inactivated farm-specific PRRSV vaccines and commercial attenuated vaccines can be useful tools to boost PRRSV-specific (humoral) immunity in sows and reduce viremia in weaned piglets. (C) 2013 Elsevier B.V. All rights reserved.