Roh Jae-Hee, Bui Ngoc Anh, Lee Hu Suk, Bui Vuong Nghia, Dao Duy Tung, Vu Thanh Thi, Hoang Thuy Thi, So Kyoung-Min, Yi Seung-Won, Kim Eunju, Hur Tai-Young, Oh Sang-Ik
Division of Animal Diseases & Health, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea.
Department of Pet Health, Kwangju Women's University, Gwangju 62396, Korea.
J Anim Sci Technol. 2021 Nov;63(6):1376-1385. doi: 10.5187/jast.2021.e103. Epub 2021 Nov 30.
Foot-and-mouth disease, one of the most contagious diseases in cloven-hoofed animals, causes significant economic losses. The pathogenesis of foot-and-mouth disease virus (FMDV) infection is known to differ with age of the animals. In this study, we aimed to reveal the difference in immunological response in the initial stage of FMDV infection between piglets and adult pigs. Peripheral blood mononuclear cells (PBMCs) were isolated from 3 piglets (8 weeks old) and 3 pigs (35 weeks old) that were not vaccinated against FMDV. O-type FMDV (2 × 10 median tissue culture infectious dose) was inoculated into porcine PBMCs and the cells were incubated at 37.0°C under 5% CO for various time periods (0, 1, 3, 6, 12, 24, and 48 h). The total RNA was obtained from the FMDV-inoculated PBMCs after each time point, and the virus titer was investigated in these RNA samples. Furthermore, dynamics of mRNA expression of the six tested cytokines (interferon [IFN]-α, IFN-γ, interleukin [IL]-6, IL-8, IL-10, and tumor necrosis factor [TNF]-α) in FMDV-inoculated porcine PBMCs were evaluated by time-series analysis to determine the differences, if any, based on the age of the pigs. The PBMCs of piglets contained the highest quantity of FMDV mRNA at 6 hours post-inoculation (hpi), and the PBMCs of pigs had the highest quantity of FMDV mRNA at 3 hpi. The mean cycle threshold-value in the PBMCs steadily decreased after the peak time point in the piglets and pigs (6 and 3 hpi, respectively). The dynamics of mRNA expression of all cytokines except TNF-α showed age-dependent differences in FMDV-inoculated PBMCs. The mRNA expression of most cytokines was more pronounced in the piglets than in the pigs, implying that the immune response against FMDV showed an age-dependent difference in pigs. In conclusion, within 48 hpi, the 8-week-old piglets responded more rapidly and were more sensitive to FMDV infection than the 35-week-old pigs, which could be associated with the difference in the pathogenesis of FMDV infection among the pigs. These results provide valuable insights into the mechanisms underlying the age-dependent differences in immune response in pigs against FMDV infection.
口蹄疫是偶蹄动物中传染性最强的疾病之一，会造成重大经济损失。已知口蹄疫病毒（FMDV）感染的发病机制因动物年龄而异。在本研究中，我们旨在揭示仔猪和成年猪在FMDV感染初期免疫反应的差异。从未接种过FMDV疫苗的3头仔猪（8周龄）和3头猪（35周龄）中分离外周血单核细胞（PBMC）。将O型FMDV（2×10个半数组织培养感染剂量）接种到猪PBMC中，并将细胞在37.0°C、5%二氧化碳条件下孵育不同时间段（0、1、3、6、12、24和48小时）。在每个时间点后从接种FMDV的PBMC中获取总RNA，并在这些RNA样本中检测病毒滴度。此外，通过时间序列分析评估接种FMDV的猪PBMC中六种检测细胞因子（干扰素[IFN]-α、IFN-γ、白细胞介素[IL]-6、IL-8、IL-10和肿瘤坏死因子[TNF]-α）的mRNA表达动态，以确定基于猪年龄的差异（如有）。仔猪的PBMC在接种后6小时（hpi）含有最高量的FMDV mRNA，猪的PBMC在3 hpi含有最高量的FMDV mRNA。仔猪和猪在达到峰值时间点（分别为6和3 hpi）后，PBMC中的平均循环阈值稳步下降。在接种FMDV的PBMC中，除TNF-α外，所有细胞因子的mRNA表达动态均显示出年龄依赖性差异。大多数细胞因子的mRNA表达在仔猪中比在猪中更明显，这意味着猪对FMDV的免疫反应表现出年龄依赖性差异。总之，在48 hpi内，8周龄的仔猪比35周龄的猪对FMDV感染反应更快且更敏感，这可能与猪中FMDV感染发病机制的差异有关。这些结果为猪对FMDV感染免疫反应中年龄依赖性差异的潜在机制提供了有价值的见解。
