Abstract：
We previously described cardiomyocyte abnormality caused by Km_5666 strain, a variant of fowl glioma-inducing virus (FGV) prototype, which is an avian leukosis virus (ALV). However, the cardiac involvement appeared to be eradicated from the flock after a few years. An epidemiological survey from 2017 to 2020 was performed to elucidate the current prevalence of the cardiopathogenic strains in this flock. Four of the 71 bantams pathologically examined showed both glioma and cardiomyocyte abnormality, from which three ALV strains were detected. DNA sequencing revealed that several different ALV strains coexisted in each bantam and that the conserved Km_5666 virus fluid also contained at least two different ALV strains. We generated three infectious molecular clones from these samples, named KmN_77_clone_A, KmN_77_clone_B, and Km_5666_clone. The envSU of KmN_77_clone_A shared high sequence identity with that of Km_5666 (94.1%). In contrast, the envSU of KmN_77_clone_B showed >99.2% nucleotide similarity with that of an FGV variant without cardiopathogenicity. Furthermore, Km_5666_clone experimentally reproduced both gliomas and cardiomyocyte abnormality in chickens. From these results, it is suggested that the pathogenic determinant of cardiomyocyte abnormality is located in envSU similar to that of Km_5666. The cloning technique described here is beneficial for evaluating the viral pathogenicity in cases where affected birds are coinfected with several different ALV strains.
摘要：
我们先前描述了由Km_5666菌株引起的心肌细胞异常，禽类神经胶质瘤诱导病毒（FGV）原型的变体，属于禽白血病病毒（ALV）。然而,几年后，心脏受累似乎从羊群中根除。进行了2017年至2020年的流行病学调查，以阐明该群中心脏致病菌株的当前患病率。经病理检查的71只小鸡中，有4只显示神经胶质瘤和心肌细胞异常，从中检测到三个ALV菌株。DNA测序揭示了几种不同的ALV毒株共存于每个矮脚鸡,并且保守的Km_5666病毒液也包含至少两种不同的ALV毒株。我们从这些样本中产生了三个感染性分子克隆，名为KmN_77_clone_A，KmN_77_clone_B,和Km_5666_clone。KmN_77_clone_A的envSU与Km_5666具有很高的序列同一性（94.1％）。相比之下,KmN_77_clone_B的envSU与无心脏致病性的FGV变体的核苷酸相似性>99.2％。此外，Km_5666_克隆通过实验复制了鸡的神经胶质瘤和心肌细胞异常。从这些结果来看,提示envSU中存在与Km_5666相似的心肌细胞异常致病因素。在受影响的鸟类与几种不同的ALV毒株共感染的情况下，此处描述的克隆技术对于评估病毒致病性是有益的。
