Wang Huiwen, Logue Catherine M, Nolan Lisa K, Lin Jun
Department of Animal Science, University of Tennessee, Knoxville, TN 37919, USA.
Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
Pathogens. 2023 Jul 31;12(8):1002. doi: 10.3390/pathogens12081002.
Colibacillosis, caused by avian pathogenic (APEC), is an important infectious disease in chickens and a major cause of mortality in young chicks. Therefore, protecting young chickens from colibacillosis is important for improving welfare and productivity in the poultry industry. Recently, we developed a novel enterobactin (Ent) conjugate vaccine that could induce high titers of anti-Ent immunoglobulin Y (IgY) in chicken serum and consequently mitigate the organ lesions caused by APEC infection. Considering that maternal immunization is a practical approach to confer instant immune protection to the hatchlings, in this study, we immunized breeder hens with the Ent conjugate vaccine and evaluated the maternal immune protection on the progenies challenged with APEC. Three doses of the vaccine induced high titers of anti-Ent IgY in the hens (about 16- and 64-fold higher than the control group in the sera and egg yolks, respectively), resulting in an eight-fold of increase in anti-Ent IgY in the sera of progenies. However, the anti-Ent maternal immunity did not display significant protection against APEC challenge in the young chicks as there was no significant difference in APEC load (in liver, lung, and spleen) or organ lesions (in heart, liver, spleen, lung, and air sac) between the vaccinated and control groups. In future studies, the APEC infection model needs to be optimized to exhibit proper pathogenicity of APEC, and the maternal immunization regimen can be further improved to boost the maternally derived anti-Ent IgY in the hatchlings.
禽致病性大肠杆菌（APEC）引起的大肠杆菌病是鸡的一种重要传染病，也是幼雏死亡的主要原因。因此，保护幼鸡免受大肠杆菌病感染对于提高家禽业的福利和生产力至关重要。最近，我们开发了一种新型的肠杆菌素（Ent）缀合物疫苗，该疫苗可在鸡血清中诱导高滴度的抗Ent免疫球蛋白Y（IgY），从而减轻APEC感染引起的器官损伤。考虑到母体免疫是一种为雏鸡提供即时免疫保护的实用方法，在本研究中，我们用Ent缀合物疫苗免疫种母鸡，并评估了对受APEC攻击的后代的母体免疫保护作用。三剂疫苗在母鸡中诱导出高滴度的抗Ent IgY（血清和蛋黄中的滴度分别比对照组高约16倍和64倍），导致后代血清中抗Ent IgY增加了八倍。然而，抗Ent母体免疫在幼雏中并未对APEC攻击显示出显著的保护作用，因为接种疫苗组和对照组之间的APEC载量（在肝脏、肺和脾脏中）或器官损伤（在心脏、肝脏、脾脏、肺和气囊中）没有显著差异。在未来的研究中，需要优化APEC感染模型以展现APEC的适当致病性，并且可以进一步改进母体免疫方案以提高雏鸡中母体来源的抗Ent IgY水平。
