Boehringer Ingelheim Veterinary Research Center GmbH & Co. KG., Hanover, Germany.
Boehringer Ingelheim Vetmedica GmbH, Ingelheim, Germany.
PLoS One. 2019 Oct 2;14(10):e0223060. doi: 10.1371/journal.pone.0223060. eCollection 2019.
In this study, we analyzed PRRS virus (PRRSv) specific lymphocyte function in piglets vaccinated with Ingelvac PRRSFLEX EU® at two and three weeks of age in the presence of homologous maternal immunity. Complete analysis of maternal immunity to PRRSv was evaluated postpartum, as well as passive transfer of antibodies and T cells to the piglet through colostrum intake and before and after challenge with a heterologous PRRSv at ten weeks of age. Maternal-derived antibodies were detected in piglets but declined quickly after weaning. However, vaccinated animals restored PRRSv-specific antibody levels by anamnestic response to vaccination. Cell analysis in colostrum and milk revealed presence of PRRSv-specific immune cells at suckling with higher concentrations found in colostrum than in milk. In addition, colostrum and milk contained PRRSv-specific IgA and IgG that may contribute to protection of newborn piglets. Despite the presence of PRRSv-specific Peripheral Blood Mononuclear cells (PBMCs) in colostrum and milk, no PRRSv-specific cells could be detected from blood of the piglets at one or two weeks of life. Nevertheless, cellular immunity was detectable in pre-challenged piglets up to 7 weeks after vaccination while the non-vaccinated control group showed no interferon (IFN) γ response to PRRSv stimulation. After challenge, all piglets developed a PRRSv-specific IFNγ-response, which was more robust at significantly higher levels in vaccinated animals compared to the primary response to PRRSv in non-vaccinated animals. Cytokine analysis in the lung lumen showed a reduction of pro-inflammatory responses to PRRSv challenge in vaccinated animals, especially reduced interferon (IFN) α levels. In conclusion, vaccination of maternally positive piglets at 2 and 3 weeks of age with Ingelvac PRRSFLEX EU induced a humoral and cellular immune response to PRRSv and provided protection against virulent, heterologous PRRSv challenge.
在本研究中，我们分析了在存在同源母源抗体的情况下，于 2 周和 3 周龄用 Ingelvac PRRSFLEX EU®对仔猪进行疫苗接种后 PRRS 病毒（PRRSv）特异性淋巴细胞功能。在 10 周龄用异源 PRRSv 攻毒前、后，通过仔猪吮乳被动转移抗体和 T 细胞，对仔猪的母源 PRRSv 抗体进行了全面分析。在仔猪中检测到母源抗体，但在断奶后迅速下降。然而，通过疫苗接种的回忆反应，接种动物恢复了 PRRSv 特异性抗体水平。在吮乳时，从初乳和乳中分离出的细胞分析中发现存在 PRRSv 特异性免疫细胞，且初乳中的浓度高于乳中。此外，初乳和乳中含有 PRRSv 特异性 IgA 和 IgG，可能有助于保护新生仔猪。尽管在初乳和乳中存在 PRRSv 特异性外周血单核细胞（PBMCs），但在 1 或 2 周龄仔猪的血液中未检测到 PRRSv 特异性细胞。然而，在接种疫苗后 7 周内，预攻毒仔猪可检测到细胞免疫，而未接种疫苗的对照组对 PRRSv 刺激无干扰素（IFN）γ反应。攻毒后，所有仔猪均产生 PRRSv 特异性 IFNγ-反应，与未接种疫苗动物对 PRRSv 的初次反应相比，在接种疫苗动物中反应更为强烈。在肺腔腔室中的细胞因子分析表明，接种疫苗动物的 PRRSv 攻毒后促炎反应减少，尤其是干扰素（IFN）α水平降低。总之，在 2 周和 3 周龄时对母源阳性仔猪用 Ingelvac PRRSFLEX EU 进行疫苗接种可诱导针对 PRRSv 的体液和细胞免疫反应，并提供针对强毒异源 PRRSv 攻毒的保护。
