Tan Lei, Qiu Xusheng, Liang Lujing, Liao Xin, Wang Fei, Sun Yingjie, Song Cuiping, Liao Ying, Ding Chan
Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
Front Microbiol. 2024 Jul 31;15:1458252. doi: 10.3389/fmicb.2024.1458252. eCollection 2024.
Newcastle Disease (ND) and Infectious Bronchitis (IB) are two significant diseases that pose threats to the poultry industry, caused by Newcastle disease virus (NDV) and Infectious bronchitis virus (IBV), respectively. Currently, the control and prevention of these diseases primarily rely on vaccination. However, commercial ND and IB vaccines face challenges such as poor cross-protection of inactivated IBV strains and interference from live vaccines when used together, leading to immunization failures. Previously, we reported the successful rescue of a recombinant NDV expressing multiple epitopes of IBV, named rNDV-IBV-T/B, which showed promising immunoprotective efficacy against both NDV and IBV. This study focuses on the biosafety of the genetically modified recombinant vaccine candidate rNDV-IBV-T/B. Immunization was performed on day-old chicks, ducklings, goslings, and ICR mice. Observations were recorded on clinical symptoms, body weight changes, and post-mortem examination of organs, as well as histopathological preparations of tissue samples. The results indicated that the rNDV-IBV-T/B vaccine candidate had no adverse effects on the growth of targeted animals (chickens) and non-target species (ducks, geese) as well as in mammals (mice). Additionally, histopathological slides confirmed that the vaccine is safe for all tested species. Further studies evaluated the potential of rNDV-IBV-T/B to spread horizontally and vertically post-immunization, and its environmental safety. The findings revealed that the vaccine candidate lacks the capability for both horizontal and vertical transmission and does not survive in the environment. In conclusion, the rNDV-IBV-T/B strain is safe and holds potential as a new chimeric live vaccine for ND and IB.
新城疫（ND）和传染性支气管炎（IB）是对家禽业构成威胁的两种重要疾病，分别由新城疫病毒（NDV）和传染性支气管炎病毒（IBV）引起。目前，这些疾病的防控主要依靠疫苗接种。然而，商业化的新城疫和传染性支气管炎疫苗面临着诸如灭活传染性支气管炎病毒株交叉保护效果差以及活疫苗联合使用时相互干扰等挑战，从而导致免疫失败。此前，我们报道了成功拯救出一种表达传染性支气管炎病毒多个表位的重组新城疫病毒，命名为rNDV-IBV-T/B，它对新城疫病毒和传染性支气管炎病毒均显示出有前景的免疫保护效力。本研究聚焦于转基因重组候选疫苗rNDV-IBV-T/B的生物安全性。对一日龄雏鸡、雏鸭、雏鹅和ICR小鼠进行免疫接种。记录临床症状、体重变化、器官剖检情况以及组织样本的组织病理学制片观察结果。结果表明，候选疫苗rNDV-IBV-T/B对目标动物（鸡）、非目标物种（鸭、鹅）以及哺乳动物（小鼠）的生长均无不良影响。此外，组织病理学切片证实该疫苗对所有受试物种均安全。进一步研究评估了rNDV-IBV-T/B免疫接种后水平传播和垂直传播的可能性及其环境安全性。研究结果显示，该候选疫苗缺乏水平传播和垂直传播能力，且在环境中无法存活。总之，rNDV-IBV-T/B毒株安全，有望成为一种新型的新城疫和传染性支气管炎嵌合活疫苗。
