The immunological mechanisms of in ovo vaccination

蛋内疫苗接种是鸡孵化后疫苗接种的另一种方法。这是一种安全的、动物友好的方法，每小时可接种约6万个鸡蛋。利用病毒载体对病毒性疾病进行疫苗接种的技术已经得到了很好的发展，目前正在努力推广细菌和寄生虫疫苗技术。虽然在卵细胞中接种疫苗是成功的，但未成熟的新生儿免疫系统显示出功能缺陷，限制了这项技术的成功率。目前家禽业使用的蛋内疫苗是活的复制病毒。为了扩展和改进该技术用于灭活疫苗或佐剂亚单位疫苗的应用，了解早期生命免疫本体以及影响粘膜表面抗原摄取和诱导免疫反应的细胞和分子机制至关重要。我们将调查禽类新生儿的免疫环境是否像之前在哺乳动物中显示的那样，向th2型免疫分化，并抑制th1型反应。先天免疫也显示抗原呈递细胞的功能缺陷；toll样受体的表达和信号传导经历了与不同功能反应相关的成熟变化。因此，本项目将验证新生儿先天免疫和适应性免疫系统的固有调节约束可以通过适当的刺激来克服的假设。已经提出了各种方法，包括改进训练先天免疫，改变先天受体激动剂和新的年龄特异性调节系统。深入了解免疫本体以及影响新生儿免疫反应诱导的细胞和分子因素将是该项目的一部分。

In ovo vaccination is an alternative approach to post-hatch vaccination of chickens. It is a safe, animal and user-friendly method that enables vaccination ~60,000 eggs per hour. The technology has been well developed for vaccination against viral diseases using viral vectors and efforts to extend the technology for bacterial and parasitic vaccines are in progress. Although in ovo vaccination can be successful, the immature immune system of a neonate shows functional deficiencies that limit the success rate of this technology. The in ovo vaccines currently used in the poultry industry are live replicating viruses. To extend and improve this technology for application of inactivated vaccines or adjuvanted subunit vaccines, it is of utmost importance that we understand early life immune ontology and the cellular and molecular mechanisms that affect antigen uptake at mucosal surfaces and induction of immune responses. We will investigate if the avian neonatal immunological milieu is polarised towards Th2-type immunity with dampening of Th1-type responses as previously shown in mammals. Innate immunity also shows functional deficiency in antigen-presenting cells; expression and signalling of Toll-like receptors undergo maturational changes associated with distinct functional responses. Therefore, this project will test the hypothesis that the inherent regulatory constraints of the neonate innate and adaptive immune system can be surmounted by appropriate stimulation. A variety of approaches have been proposed including improved trained innate immunity, altered innate receptor agonists and novel age-specific adjuvantation systems. Gaining a thorough understanding of the immune ontology and cellular and molecular factors that can influence the induction of immune responses in neonates will part of this project.