Unit Viral Re-Emerging, Enzootic and Bee Diseases, Department Infectious Diseases in Animals, Sciensano, Groeselenbergstraat 99, 1180 Ukkel, Belgium.
Unit of Porcine Health Management, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
Viruses. 2023 Feb 9;15(2):479. doi: 10.3390/v15020479.
Vaccination against the porcine reproductive and respiratory syndrome virus (PRRSv) is widely used to prevent production losses in the swine industry. In this study, piglets born from both PRRSv-vaccinated ELISA-seropositive sows (E+ piglets) and PRRSv-vaccinated ELISA-seronegative sows (E- piglets) were followed-up pre-vaccination, 3 weeks post-vaccination (wpv) and 8 wpv in two Belgian farrow-to-finish herds. The aim of the study was to analyze the presence of PRRSv-specific maternally-derived antibodies (MDAs) and the PRRSv vaccine response in both groups of piglets. The E- piglets lacked the presence of PRRSv-specific MDAs (0% seropositive), while these were present in the E+ piglets (97% seropositive). Due to this, the E- piglets showed a strong initial vaccine response (72-80% seroconversion) and vaccine viremia (65-75% PCR positive) at 3 wpv. In contrast, the E+ piglets showed only limited initial vaccine responses (25-61% with increased ELISA values) and vaccine viremia (30-31% PCR positive) at 3 wpv. By 8 wpv, the proportion of seropositive E- piglets (78-100%) and seropositive E+ piglets (55-90%) increased in both herds. However, a difference in vaccine viremia duration was observed between both herds at 8 wpv, with a decrease in the proportion of PCR positive piglets in herd 1 (E-: 47%; E+: 25%) and an increase in the proportion of PCR positive piglets in herd 2 (E-: 85%; E+: 92%). This study identified clear differences in the presence of PRRSv-specific maternally-derived antibodies and PRRSv vaccine responses between E- and E+ piglets. Further research is warranted to elicit the biological relevance of these observed differences.
接种猪繁殖与呼吸综合征病毒（PRRSv）疫苗广泛用于预防养猪业的生产损失。在这项研究中，我们对来自 PRRSv 疫苗接种 ELISA 血清阳性母猪（E+仔猪）和 PRRSv 疫苗接种 ELISA 血清阴性母猪（E-仔猪）的仔猪进行了预接种、接种后 3 周（wpv）和 8 wpv 的随访。本研究旨在分析两组仔猪 PRRSv 特异性母源抗体（MDAs）的存在和 PRRSv 疫苗反应。E-仔猪缺乏 PRRSv 特异性 MDAs（0%血清阳性），而 E+仔猪则存在 PRRSv 特异性 MDAs（97%血清阳性）。因此，E-仔猪在 3 wpv 时表现出强烈的初始疫苗反应（72-80%血清转化率）和疫苗病毒血症（65-75%PCR 阳性）。相比之下，E+仔猪仅表现出有限的初始疫苗反应（25-61% ELISA 值增加）和疫苗病毒血症（30-31%PCR 阳性）在 3 wpv。到 8 wpv 时，两群 E-仔猪（78-100%）和 E+仔猪（55-90%）的血清阳性比例均增加。然而，在 8 wpv 时，两群之间观察到疫苗病毒血症持续时间存在差异，在 herd1 中，PCR 阳性仔猪的比例下降（E-：47%；E+：25%），而在 herd2 中，PCR 阳性仔猪的比例增加（E-：85%；E+：92%）。本研究确定了 E-和 E+仔猪之间 PRRSv 特异性母源抗体和 PRRSv 疫苗反应的存在存在明显差异。需要进一步研究以阐明这些观察到的差异的生物学相关性。
