Virology, Immunology, Parasitology, Aviaire et Cunicole, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Laboratoire de Ploufragan-Plouzané-Niort, Université de Rennes 1, 22440 Ploufragan, France.
Génétique Virale et Biosécurité, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Laboratoire de Ploufragan-Plouzané-Niort, Université de Rennes 1, 22440 Ploufragan, France.
Viruses. 2022 Jun 25;14(7):1392. doi: 10.3390/v14071392.
Infectious Bronchitis virus (IBV) continues to cause significant economic losses for the chicken industry despite the use of many live IBV vaccines around the world. Several authors have suggested that vaccine-induced partial protection may contribute to the emergence of new IBV strains. In order to study this hypothesis, three passages of a challenge IBV were made in SPF chickens sham inoculated or vaccinated at day of age using a live vaccine heterologous to the challenge virus. All birds that were challenged with vaccine heterologous virus were positive for viral RNA. NGS analysis of viral RNA in the unvaccinated group showed a rapid selection of seven genetic variants, finally modifying the consensus genome of the viral population. Among them, five were non-synonymous, modifying one position in NSP 8, one in NSP 13, and three in the Spike protein. In the vaccinated group, one genetic variant was selected over the three passages. This synonymous modification was absent from the unvaccinated group. Under these conditions, the genome population of an IBV challenge virus evolved rapidly in both heterologous vaccinated and non-vaccinated birds, while the genetic changes that were selected and the locations of these were very different between the two groups.
传染性支气管炎病毒（IBV）尽管在全球范围内使用了许多活的 IBV 疫苗，但仍继续给家禽业造成重大经济损失。有几位作者提出，疫苗诱导的部分保护可能导致新的 IBV 株的出现。为了研究这一假设，我们在 SPF 鸡中进行了三次挑战 IBV 的传代实验，这些鸡在出生日被假接种或用与挑战病毒具有同源性的活疫苗接种。所有用疫苗同源病毒进行攻毒的鸡都检测到了病毒 RNA 呈阳性。未接种疫苗组的病毒 RNA 的 NGS 分析显示，七个遗传变异体迅速被选择，最终改变了病毒种群的共识基因组。其中，有五个是非同义突变，分别改变了 NSP8 中的一个位置、NSP13 中的一个位置和 Spike 蛋白中的三个位置。在接种疫苗组中，这三个传代过程中只选择了一个遗传变异体。这种同义突变在未接种疫苗组中不存在。在这些条件下，IBV 挑战病毒的基因组种群在异源接种和未接种的鸟类中迅速进化，而两组之间选择的遗传变化及其位置则大不相同。
