Nedumpun Teerawut, Rungprasert Kanana, Ninvilai Patchareeporn, Limcharoen Benchaphorn, Tunterak Wikanda, Prakairungnamthip Duangduean, Techakriengkrai Navapon, Banlunara Wijit, Suradhat Sanipa, Thontiravong Aunyaratana
Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand, 10330; Center of Excellence for Emerging and Re-emerging Infectious Diseases in Animals (CUEIDAs), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand, 10330.
Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand, 10330.
Poult Sci. 2025 Feb;104(2):104731. doi: 10.1016/j.psj.2024.104731. Epub 2024 Dec 25.
Duck Tembusu virus (DTMUV), an emerging avian pathogenic flavivirus, is notably associated with neurological disorders and acute egg drop syndrome in ducks. We previously demonstrated that the susceptibility of ducks to DTMUV infection varies significantly with age, with younger ducks (4-week-old) exhibiting more severe disease than older ducks (27-week-old). However, the immunological mechanisms underlying these age-related differences in disease severity remain unclear. In this study, we investigated the dynamics of immune responses following DTMUV infection in adult laying ducks (27-week-old) and compared them to our previous findings on young ducks (4 weeks old). The numbers of T helper, cytotoxic T, B, and non-T and B lymphocytes, as well as neutralizing antibody levels, were measured in parallel with DTMUV loads in the blood and target organs. Our results revealed that the number of non-T and B lymphocytes/myeloid cells in 27-week-old adult laying ducks infected with DTMUV remained consistently stable throughout the observation period, in contrast to findings in 4-week-old younger ducks, where myeloid cell responses were implicated in disease progression. Regarding lymphocyte responses, unlike in 4-week-old younger ducks, only cytotoxic T lymphocyte responses in 27-week-old older ducks showed a significant negative correlation with the reduction of viremia and viral loads in target organs, indicating their role in controlling viral replication in older ducks. Additionally, 27-week-old adult laying ducks infected with DTMUV exhibited high levels of neutralizing antibodies, which were significantly correlated with reduced viral loads in blood and target organs. Overall, the presence of robust DTMUV-specific neutralizing antibody and CTL responses, along with a finely tuned myeloid cell response likely plays a significant role in controlling severe neurological outcomes in 27-week-old adult laying ducks. This study highlights the age-related differences in immune responses following DTMUV infection, which potentially contribute to the varying disease severity among ducks of different ages. Understanding the interplay between the host and DTMUV provides significant implications for disease management strategies and vaccine development.
鸭坦布苏病毒（DTMUV）是一种新出现的禽致病性黄病毒，与鸭的神经紊乱和急性产蛋下降综合征显著相关。我们之前证明，鸭对DTMUV感染的易感性随年龄有显著差异，幼鸭（4周龄）比成年鸭（27周龄）表现出更严重的疾病。然而，这些与年龄相关的疾病严重程度差异背后的免疫机制仍不清楚。在本研究中，我们调查了成年产蛋鸭（27周龄）感染DTMUV后免疫反应的动态变化，并将其与我们之前关于幼鸭（4周龄）的研究结果进行比较。同时测量了辅助性T细胞、细胞毒性T细胞、B细胞以及非T和B淋巴细胞的数量，以及中和抗体水平，并与血液和靶器官中的DTMUV载量进行对比。我们的结果显示，感染DTMUV的27周龄成年产蛋鸭中非T和B淋巴细胞/髓样细胞的数量在整个观察期内一直保持稳定，这与4周龄幼鸭的情况不同，在幼鸭中髓样细胞反应与疾病进展有关。关于淋巴细胞反应，与4周龄幼鸭不同，27周龄成年鸭中只有细胞毒性T淋巴细胞反应与病毒血症的降低和靶器官中病毒载量的减少呈显著负相关，表明它们在控制成年鸭病毒复制中发挥作用。此外，感染DTMUV的27周龄成年产蛋鸭表现出高水平的中和抗体，这些抗体与血液和靶器官中病毒载量的降低显著相关。总体而言，强大的DTMUV特异性中和抗体和CTL反应的存在，以及精细调节的髓样细胞反应，可能在控制27周龄成年产蛋鸭的严重神经病变中发挥重要作用。本研究突出了DTMUV感染后免疫反应的年龄相关差异，这可能导致不同年龄鸭之间疾病严重程度的差异。了解宿主与DTMUV之间的相互作用对疾病管理策略和疫苗开发具有重要意义。
