Enhancing potency and efficacy of herpesvirus of turkeys-based multivalent vaccines against avian influenza viruses

H5N1和H9N1亚型禽流感病毒会给家禽造成严重损失，并对人畜共患传染病构成风险。目前可用的针对这些病毒的灭活疫苗是在胚胎鸡蛋中生产的，有几个缺点。我们以火鸡疱疹病毒为疫苗载体，研制了一种新型活病毒载体疫苗。该疫苗是在培养细胞中制备的，在孵化前或孵化后将单剂疫苗接种到鸡蛋中，可在接种疫苗的鸡中诱导终身免疫。接种疫苗的禽类在接种疫苗后六周受到攻击时，显示出对高致病性禽流感和马立克氏病的保护作用。该项目将提高基于HVT的禽流感疫苗的效力和效力，这种疫苗将在早期(孵化后三周内)保护鸟类。此外，我们计划开发一种三价疫苗，以保护接种疫苗的鸡只免受H5和H9亚型禽流感病毒和马立克氏病的影响。

Avian influenza (AI) viruses of H5N1 and H9N2 subtypes cause severe losses in poultry and pose risks for zoonotic infections. Currently available inactivated vaccines against these viruses are produced in embryonated eggs and have several disadvantages. We have developed a novel live virus vector-based vaccine exploiting herpesvirus of turkeys (HVT) as vaccine vector. The vaccine was prepared in cultured cells, and a single dose of vaccine delivered into eggs before hatch or after hatch induced life-long immunity in vaccinated chickens. Vaccinated birds showed protection against both highly pathogenic AI and Marek's disease when challenged at six week post vaccination. This project will enhance potency and efficacy of the HVT-based AI vaccines that will protect birds at an early age (within three weeks of hatch). In addition, we plan to develop a trivalent vaccine that will protect vaccinated chickens against both H5 and H9 subtypes of avian influenza viruses and Marek's disease.