Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, People's Republic of China.
Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, People's Republic of China.
Vet Microbiol. 2020 Nov;250:108835. doi: 10.1016/j.vetmic.2020.108835. Epub 2020 Aug 28.
To develop an alternative vectored vaccine against both Newcastle disease virus (NDV) and infectious laryngotracheitis virus (ILTV), the glycoprotein C (gC) gene was first deleted from an avirulent ILTV. Based on this gC-deleted ILTV mutant, a recombinant ILTV expressing the fusion protein (F) of a genotype VII NDV (designated ILTV-ΔgC-F) was then constructed. Expression of the NDV F protein in ILTV-ΔgC-F-infected LMH cells was examined with an immunofluorescence assay and western blotting. The F gene was stably maintained in the genome of ILTV-ΔgC-F and the F protein was stably expressed. Compared with the parental virus, ILTV-ΔgC-F demonstrated an increased penetration capacity in vitro, and an increased replication rate in vitro and in vivo. Both the parental virus and ILTV-ΔgC-F were avirulent in chickens. Vaccination of specific-pathogen-free chickens with ILTV-ΔgC-F induced ILTV-specific antibodies, detected with an enzyme-linked immunosorbent assay (ELISA), and provided complete clinical protection against virulent ILTV, although viral shedding and replication were detected in the respiratory tract in the early stage of infection in a very small number of birds. Vaccination with ILTV-ΔgC-F also provided significant protection against challenge with a virulent genotype VII NDV, although the level of NDV-specific antibodies detected with an ELISA was low. Notably, the numbers of birds that were positive for the virulent genotype VII NDV and the replication of the challenge virus NDV in selected target tissues were significantly lower in the ILTV-ΔgC-F-vaccinated chickens than in the control birds. Our results indicate that ILTV-ΔgC-F has potential utility as a bivalent candidate vaccine against both infectious laryngotracheitis and Newcastle disease.
为了开发针对新城疫病毒（NDV）和传染性喉气管炎病毒（ILTV）的新型载体疫苗，首先从一种无致病性的 ILTV 中删除糖蛋白 C（gC）基因。基于这种 gC 缺失的 ILTV 突变株，构建了表达基因型 VII NDV 融合蛋白（F）的重组 ILTV（命名为 ILTV-ΔgC-F）。用免疫荧光法和 Western blot 检测了在感染 LMH 细胞的 ILTV-ΔgC-F 中的 NDV F 蛋白表达。NDV F 基因在 ILTV-ΔgC-F 的基因组中稳定维持，并且 F 蛋白稳定表达。与亲本病毒相比，ILTV-ΔgC-F 在体外具有更高的穿透能力，并且在体外和体内具有更高的复制率。亲本病毒和 ILTV-ΔgC-F 在鸡中均无致病性。用 ILTV-ΔgC-F 免疫 SPF 鸡，可诱导产生针对 ILTV 的特异性抗体，通过酶联免疫吸附试验（ELISA）检测到，并且对强毒 ILTV 提供完全的临床保护，尽管在感染早期的极少数鸟类中检测到呼吸道中的病毒脱落和复制。用 ILTV-ΔgC-F 免疫接种还为针对强毒基因型 VII NDV 的攻毒提供了显著保护，尽管 ELISA 检测到的 NDV 特异性抗体水平较低。值得注意的是，在接种 ILTV-ΔgC-F 的鸡中，检测到强毒基因型 VII NDV 的阳性鸟和选定靶组织中攻毒病毒 NDV 的复制数量明显低于对照组。我们的结果表明，ILTV-ΔgC-F 作为针对传染性喉气管炎和新城疫的二价候选疫苗具有潜在的用途。
