Dunn John R, Reddy Sanjay M, Niikura Masahiro, Nair Venugopal, Fulton Janet E, Cheng Hans H
A United States Department of Agriculture, Agricultural Research Service, U.S. National Poultry Research Center, Avian Disease and Oncology Laboratory, East Lansing, MI 48823.
B College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843.
Avian Dis. 2017 Mar;61(1):107-114. doi: 10.1637/0005-2086-61.1.107.
Marek's disease virus (MDV) is an alphaherpesvirus that causes Marek's disease (MD), a lymphoproliferative disease in chickens. Understanding of MDV gene function advanced significantly following the cloning of the MDV genome as either a series of overlapping cosmids or as a bacterial artificial chromosome (BAC), both of which could produce viable MDV. The objectives of this study were to compare multiple virulent MDV BAC clones using the Avian Disease and Oncology Laboratory's pathotyping assay, and to demonstrate the use of these clones as standardized reagents for a modified pathotyping assay by other laboratories. To date, MDV BAC clones have been produced for at least 10 MDV strains from all three serotypes including several virulent serotype 1 strains. We determined that MDV BAC clones exist for each virulent pathotype, despite the fact that these clones are not always equal in virulence to their corresponding parental strains. One clone from each pathotype was further evaluated in commercial specific-pathogen-free (SPF) chickens and found suitable for use in assays such as best-fit pathotyping, although results were variable based on the source of the SPF birds. The benefits of using BAC clones, which include easy shipping, ability to more easily manipulate, and long-term ability to use at a low passage level, are likely to result in the use of BAC clones as standard reagents for MD research. The use of the defined set of clones should allow side-by-side comparison, allowing researchers to better interpret results produced in different laboratories using different MDV field strains. Furthermore, a modified best-fit pathotyping assay has been proposed using these clones and reduced bird numbers.
马立克氏病病毒（MDV）是一种α疱疹病毒，可引发马立克氏病（MD），这是一种鸡的淋巴细胞增生性疾病。随着MDV基因组被克隆为一系列重叠黏粒或细菌人工染色体（BAC），人们对MDV基因功能的理解有了显著进展，这两种方法都能产生有活性的MDV。本研究的目的是使用禽病与肿瘤学实验室的致病型分析方法比较多个强毒MDV BAC克隆，并证明这些克隆可作为标准化试剂供其他实验室用于改良致病型分析。到目前为止，已经为所有三种血清型的至少10种MDV毒株制备了MDV BAC克隆，包括几种强毒血清1型毒株。我们确定每种强毒致病型都存在MDV BAC克隆，尽管这些克隆的毒力与其相应亲本毒株并不总是相等。从每种致病型中选取一个克隆在商业无特定病原体（SPF）鸡中进一步评估，发现适用于最佳拟合致病型分析等检测，不过结果因SPF鸡的来源而异。使用BAC克隆的好处包括易于运输、更易于操作以及能够在低传代水平长期使用，这可能会导致BAC克隆被用作MD研究的标准试剂。使用一组定义好的克隆应该能够进行并排比较，使研究人员能够更好地解释不同实验室使用不同MDV田间毒株所产生的结果。此外，已经提出使用这些克隆并减少鸡的数量来进行改良的最佳拟合致病型分析。
