Genogroup II, genotype 4 noroviruses (GII.4 NoVs) are a leading cause of epidemic and sporadic acute non-bacterial gastroenteritis worldwide. In this study, we isolated a GII.4 NoV strain (designated 2015HN08) from a kid presenting with acute gastroenteritis and determined its near-complete genome sequence. We then performed sequence analysis by comparing this strain with the prototypical GII.4 strain. Virus-like particles (VLPs) derived from the major capsid protein (VP1) were expressed by using a recombinant-baculovirus expression system, and monoclonal antibodies (mAbs) were produced to compare changes in antigenic or histo-blood group antigens (HBGAs) binding sites with the previously characterized GII.4 NoV strain (JZ403). The genome of 2015HN08 was 7559 nucleotides (nt) long, excluding the poly(A) tail. Genotyping analysis indicated that this strain was a Sydney 2012 variant. In comparison with the prototype Sydney 2012 strain, there were 74, 35, and 16 differences in nucleotide sequences in ORF1, OFR2, and OFR3, causing 7, 10, and 6 amino acid (aa) changes, respectively. Expression of VP1 led to successful assembly of VLPs, as demonstrated by electron microscopy. Screening of hybridoma cell supernatants with an in vitro VLP–HBGAs binding blockade assay led to the identification of a cell clone 3G10 that exhibited HBGA-blocking effects. This mAb also exhibited blocking effects against JZ403 strain, suggesting maintenance of the antigenic site and/or HBGAs binding sites between the two strains. In summary, we determined the near-complete genome sequence of a GII.4 Sydney 2012 variant and produced an mAb with blocking effects that might be useful in evaluating the evolution of current Sydney 2012 NoV strains.

基因组II，基因型4诺如病毒（GII.4 NoVs）是全世界流行和偶发性急性非细菌性肠胃炎的主要原因。在这项研究中，我们从患有急性胃肠炎的孩子中分离出了GII.4 NoV株（命名为2015HN08），并确定了其近乎完整的基因组序列。然后，我们通过将该菌株与原型GII.4菌株进行比较来进行序列分析。使用重组杆状病毒表达系统表达主要衣壳蛋白（VP1）衍生的病毒样颗粒（VLP），并生产单克隆抗体（mAb）来比较抗原或组织血型抗原（HBGA）结合的变化位点具有先前表征的GII.4 NoV菌株（JZ403）。2015HN08的基因组长7559个核苷酸（nt），不包括poly（A）尾巴。基因分型分析表明，该菌株是2012年悉尼的变种。与原型Sydney 2012菌株相比，ORF1，OFR2和OFR3的核苷酸序列存在74、35和16的差异，分别导致7、10和6个氨基酸（aa）的变化。电子显微镜显示，VP1的表达导致VLP的成功组装。通过体外VLP-HBGAs结合阻断试验筛选杂交瘤细胞上清液，从而鉴定出具有HBGA阻断作用的细胞克隆3G10。该mAb还表现出对JZ403菌株的阻断作用，表明维持了两个菌株之间的抗原位点和/或HBGA结合位点。总之，我们确定了GII的近乎完整的基因组序列。