Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
Department of Farm Resources and Production Medicine, Faculty of Veterinary Medicine Kamphaeng Saen Campus, Kasetsart University, Nakon Pathom, Thailand.
Sci Rep. 2020 Feb 3;10(1):1649. doi: 10.1038/s41598-020-58626-y.
Cell-mediated immunity (CMI), IL-10, and the protective efficacy of modified-live porcine reproductive and respiratory syndrome virus (PRRSV) vaccines (MLV) against co-challenge with PRRSV-1 and PRRSV-2 (HP-PRRSV) were investigated. Seventy, PRRSV-free, 3-week old, pigs were allocated into 7 groups. Six groups were intramuscularly vaccinated with MLV, including Porcilis (PRRSV-1 MLV, MSD Animal Health, The Netherlands), Amervac (PRRSV-1 MLV, Laboratorios Hipra, Spain), Fostera (PRRSV-2 MLV, Zoetis, USA), Ingelvac PRRS MLV and Ingelvac PRRS ATP (PRRSV-2, Boehringer Ingelheim, USA), and Prime Pac PRRS (PRRSV-2 MLV, MSD Animal Health, The Netherlands). Unvaccinated pigs were left as control. Lymphocyte proliferative response, IL-10 and IFN-γ production were determined. At 35 days post-vaccination (DPV), all pigs were inoculated intranasally with 2 ml of each PRRSV-1 (10 TCID/ml) and PRRSV-2 (10 TCID/ml, HP-PRRSV). Following challenge, sera were quantitatively assayed for PRRSV RNA. Pigs were necropsied at 7 days post-challenge. Viremia, macro- and microscopic lung lesion together with PRRSV antigen presence were evaluated in lung tissues. The results demonstrated that, regardless of vaccine genotype, CMI induced by all MLVs was relatively slow. Increased production of IL-10 in all vaccinated groups was observed at 7 and 14 DPV. Pigs in Amervac, Ingelvac MLV and Ingelvac ATP groups had significantly higher levels of IL-10 compared to Porcilis, Fostera and Prime Pac groups at 7 and 14 DPV. Following challenge, regardless to vaccine genotype, vaccinated pigs had significantly lower lung lesion scores and PRRSV antigens than those in the control group. Both PRRSV-1 and PRRSV-2 RNA were significantly reduced. Prime Pac pigs had lowest PRRSV-1 and PRRSV-2 RNA in serum, and micro- and macroscopic lung lesion scores (p < 0.05) compared to other vaccinated groups. In conclusion, PRRSV MLVs, regardless of vaccine genotype, can reduce viremia and lung lesions following co-challenge with PRRSV-1 and PRRSV-2 (HP-PRRSV). The main difference between PRRSV MLV is the production of IL-10 following vaccination.
本研究旨在探究细胞介导免疫（CMI）、白细胞介素 10（IL-10）和改良活疫苗（MLV）对猪繁殖与呼吸综合征病毒（PRRSV）1 型和 2 型（HP-PRRSV）混合感染的保护效果。70 头无 PRRSV 的 3 周龄猪被分为 7 组。6 组猪肌肉注射 MLV，包括 Porcilis（PRRSV-1 MLV，默沙东动物保健，荷兰）、Amervac（PRRSV-1 MLV，Laboratorios Hipra，西班牙）、Fostera（PRRSV-2 MLV，Zoetis，美国）、Ingelvac PRRS MLV 和 Ingelvac PRRS ATP（PRRSV-2，辉瑞，美国）和 Prime Pac PRRS（PRRSV-2 MLV，默沙东动物保健，荷兰）。未接种疫苗的猪作为对照。测定淋巴细胞增殖反应、IL-10 和 IFN-γ 的产生。在接种后 35 天（DPV），所有猪经鼻腔接种各 2ml 的 PRRSV-1（10TCID/ml）和 PRRSV-2（10TCID/ml，HP-PRRSV）。攻毒后，定量检测血清中 PRRSV RNA。攻毒后 7 天进行剖检。评估肺组织中的病毒血症、宏观和微观肺病变以及 PRRSV 抗原的存在。结果表明，无论疫苗基因型如何，所有 MLV 诱导的细胞介导免疫反应相对较慢。所有接种组在 7 和 14 DPV 时均观察到 IL-10 的产生增加。在 7 和 14 DPV 时，Amervac、Ingelvac MLV 和 Ingelvac ATP 组的猪与 Porcilis、Fostera 和 Prime Pac 组相比，IL-10 水平显著更高。攻毒后，无论疫苗基因型如何，接种疫苗的猪的肺病变评分和 PRRSV 抗原均显著低于对照组。PRRSV-1 和 PRRSV-2 RNA 均显著减少。与其他接种组相比，Prime Pac 猪的血清 PRRSV-1 和 PRRSV-2 RNA 以及微观和宏观肺病变评分最低（p<0.05）。总之，PRRSV MLV 可降低 PRRSV-1 和 PRRSV-2（HP-PRRSV）混合感染后的病毒血症和肺病变。PRRSV MLV 的主要区别在于接种后的 IL-10 产生。
