Liu Wenkuan, Zhang Li, Cai Yong, Zhang Qiong, Chen Dehui, Qiu Shuyan, Wang Yanqun, Xu Duo, Gu Shujun, Li Xiao, Dai Jing, Liu Qian, Zhou Rong, Tian Xingui
State Key Laboratory of Respiratory Diseases, National Clinical Research Center for Respiratory Disease, Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Institute of Respiratory Health Guangzhou Medical University, Guangzhou, China.
Guangzhou Laboratory, Guangzhou, China.
Front Microbiol. 2022 Jun 16;13:924172. doi: 10.3389/fmicb.2022.924172. eCollection 2022.
Human adenovirus type 21 (HAdV-21) is an important pathogen associated with acute respiratory infection (ARI), but it was rarely reported and characterized so far. In this study, 151 of 1,704 (8.9%) pediatric patients (≤14 years old) hospitalized with ARI in Guangzhou, China in 2019 were positive for HAdV which was the third most frequently detected pathogen. Two HAdV-21-positive patients presented with severe lower respiratory illness and had similar initial symptoms at onset of illness. Then two HAdV-21 strains were isolated and characterized. The two HAdV-21 strains were sequenced and classified as subtype 21a with genomes closely related to strain BB/201903 found in Bengbu, China in March 2019. Phylogenetic analysis for whole genome and major antigen proteins of global HAdV-21 strains showed that HAdV-21 could be classified into two branches, branch 1 including genotype 21p, branch 2 including all other strains dividing into genotype 21a and 21b. There was no significant difference in the plaque size, or the replication curves between the two HAdV-21a strains and the prototype strain HAdV-21p AV-1645. However, there were five highly variable regions (HVR1, HVR3, HVR4, HVR5, and HVR7) in the hexon protein that varied between two branches. Mice immunized with one branch strain showed 2-4-fold lower neutralizing antibody titers against another branch strain. In summary, this study firstly reported two HAdV-21a infections of children in China, characterized two isolates of HAdV-21a associated with severe lower respiratory illness; our results could be important for understanding the HAdV-21 epidemiology and pathogenic, and for developing HAdV-21 vaccine and drug.
人21型腺病毒（HAdV-21）是与急性呼吸道感染（ARI）相关的一种重要病原体，但迄今为止其报道和特征描述较少。在本研究中，2019年在中国广州因ARI住院的1704名14岁及以下儿科患者中，有151名（8.9%）HAdV检测呈阳性，是第三常见的病原体。两名HAdV-21阳性患者表现为严重的下呼吸道疾病，发病初期有相似的初始症状。随后分离并鉴定了两株HAdV-21毒株。对这两株HAdV-21毒株进行测序，分类为21a亚型，其基因组与2019年3月在中国蚌埠发现的BB/201903毒株密切相关。对全球HAdV-21毒株的全基因组和主要抗原蛋白进行系统发育分析表明，HAdV-21可分为两个分支，分支1包括21p基因型，分支2包括所有其他毒株，再分为21a和21b基因型。两株HAdV-21a毒株与原型毒株HAdV-21p AV-1645在噬斑大小或复制曲线方面无显著差异。然而，六邻体蛋白中有五个高变区（HVR1、HVR3、HVR4、HVR5和HVR7）在两个分支之间存在差异。用一个分支毒株免疫的小鼠对另一个分支毒株的中和抗体滴度低2至4倍。总之，本研究首次报道了中国儿童的两例HAdV-21a感染，鉴定了两株与严重下呼吸道疾病相关的HAdV-21a分离株；我们的结果对于了解HAdV-21的流行病学和致病性，以及开发HAdV-21疫苗和药物可能具有重要意义。
