Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.
College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea.
PLoS One. 2020 Mar 2;15(3):e0229082. doi: 10.1371/journal.pone.0229082. eCollection 2020.
Gallid alphaherpesvirus 1 causes infectious laryngotracheitis (ILT) in farmed poultry worldwide. Intertypic recombination between vaccine strains of this virus has generated novel and virulent isolates in field conditions. In this study, in vitro and in ovo systems were co-infected and superinfected under different conditions with two genomically distinct and commonly used ILTV vaccines. The progeny virus populations were examined for the frequency and pattern of recombination events using multi-locus high-resolution melting curve analysis of polymerase chain reaction products. A varied level of recombination (0 to 58.9%) was detected, depending on the infection system (in ovo or in vitro), viral load, the composition of the inoculum mixture, and the timing and order of infection. Full genome analysis of selected recombinants with different in vitro phenotypes identified alterations in coding and non-coding regions. The ability of ILTV vaccines to maintain their capacity to recombine under such varied conditions highlights the significance of recombination in the evolution of this virus and demonstrates the capacity of ILTV vaccines to play a role in the emergence of recombinant viruses.
禽传染性喉气管炎病毒 1 型（Gallid alphaherpesvirus 1）可引起世界范围内养殖家禽的传染性喉气管炎（Infectious laryngotracheitis，ILT）。该病毒的疫苗株之间的异型重组在野外条件下产生了新型且具有强毒力的分离株。在这项研究中，使用两种具有不同基因组且常用的 ILTV 疫苗，在不同条件下通过体外和鸡胚系统共感染和超感染，研究了重组事件的频率和模式。使用聚合酶链反应产物的多位点高分辨率熔解曲线分析，对后代病毒群体进行了重组事件的频率和模式的检测。检测结果显示，重组水平（0 至 58.9%）取决于感染系统（鸡胚或体外）、病毒载量、接种物混合物的组成、感染的时间和顺序。对具有不同体外表型的选定重组体进行全基因组分析，确定了编码和非编码区的改变。ILTV 疫苗在如此多样化的条件下保持其重组能力的能力突显了重组在该病毒进化中的重要性，并证明了 ILTV 疫苗在重组病毒出现中发挥作用的能力。
