Kyushu Research Station, National Institute of Animal Health (NIAH), National Agriculture and Food Research Organization (NARO), 2702 Chuzan, Kagoshima, Kagoshima, 891-0105, Japan.
Division of Viral Disease and Epidemiology, NIAH, NARO, 3-1-5 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.
Vet Res. 2021 Jan 4;52(1):2. doi: 10.1186/s13567-020-00880-z.
Porcine epidemic diarrhea (PED) is a coronavirus disease characterized by the rapid spread of severe diarrhea among pigs. PED virus (PEDV) infects and replicates mainly in the epithelial cells of the duodenum, jejunum, ileum and colon. Serum or mucosal IgA antibody levels have been used to predict both vaccine efficacy and the level of protective immunity to enteric infectious diseases in individuals or herds. Details of the B-cell immune response upon PEDV infection, such as the systemic and mucosal PEDV IgA antibody response, the distribution of IgA antibody-secreting cells (ASCs), and their role in virus clearance are not yet clear. In this experimental infection study, we observed similar fluctuations in PEDV IgA antibody levels in serum and intestinal contents of the upper and lower jejunum and ileum, but not fecal samples, over the 4-week experimental course. ASCs that actively secrete PEDV IgA antibody without in vitro stimulation were distributed mainly in the upper jejunum, whereas memory B cells that showed enhanced PEDV IgA antibody production upon in vitro stimulation were observed in mesenteric lymph nodes and the ileum. Our findings will contribute to the development of effective vaccines and diagnostic methods for PEDV.
猪流行性腹泻（PED）是一种冠状病毒病，其特征是猪群中严重腹泻迅速传播。猪流行性腹泻病毒（PEDV）主要感染和复制猪的十二指肠、空肠、回肠和结肠的上皮细胞。血清或黏膜 IgA 抗体水平已被用于预测个体或群体对肠道传染病的疫苗效力和保护免疫水平。PEDV 感染后 B 细胞免疫反应的细节，如系统和黏膜 PEDV IgA 抗体反应、分泌 IgA 抗体的细胞（ASC）的分布及其在清除病毒中的作用尚不清楚。在这项实验感染研究中，我们观察到在 4 周的实验过程中，在上、下空肠和回肠的血清和肠内容物中，PEDV IgA 抗体水平相似的波动，但粪便样本中没有。未经体外刺激主动分泌 PEDV IgA 抗体的 ASC 主要分布在上空肠，而在体外刺激下表现出增强的 PEDV IgA 抗体产生的记忆 B 细胞则存在于肠系膜淋巴结和回肠中。我们的发现将有助于开发有效的 PEDV 疫苗和诊断方法。
