Abstract：
Unlike pandemic GII.4 norovirus, GII.6 norovirus shows limited sequence variation in its major capsid protein VP1. In this study, we investigated the VP1 expression profiles, binding abilities, and cross-blocking effects of three GII.6 norovirus strains derived from three distinct variants. Norovirus VP1 was expressed using a recombinant baculovirus expression system and characterized by transmission electron microscopy, mass spectrometry, salivary histo-blood group antigen (HBGA)-virus like particles (VLPs) binding and binding blockade assays. Mass spectrometry revealed the expected molecular weight (MW) of full-length proteins and degraded or cleaved fragments of all three VP1 proteins. Peptide mapping showed loss of 2 and 3 amino acids from the N- and C-terminus, respectively. Further, the co-expression of VP1 and VP2 proteins did not lead to extra fragmentation during mass spectrometry. Salivary HBGA-VLP binding assay revealed similar binding patterns of the three GII.6 VP1 proteins. Salivary HBGA-VLP binding blockade assay induced cross-blocking effects. Our results demonstrate similar binding abilities against salivary HBGAs and specific cross-blocking effects for GII.6 norovirus strains derived from distinct variants, suggesting that fewer GII.6 strains from different evolutionary variants are needed for the development of norovirus vaccines.
摘要：
与大流行GII4诺如病毒不同，GII.6诺如病毒在其主要衣壳蛋白VP1中显示有限的序列变异。在这项研究中,我们调查了VP1表达谱，结合能力，和来自三种不同变体的三种GII.6诺如病毒株的交叉阻断作用。使用重组杆状病毒表达系统表达诺如病毒VP1，并通过透射电子显微镜表征，质谱,唾液组织血型抗原（HBGA）-病毒样颗粒（VLP）结合和结合阻断测定。质谱分析显示了全长蛋白和所有三种VP1蛋白的降解或裂解片段的预期分子量(MW)。肽图谱显示从N-和C-末端丢失2和3个氨基酸，分别。Further,VP1和VP2蛋白的共表达在质谱分析过程中不会导致额外的片段化.唾液HBGA-VLP结合测定揭示了三种GII.6VP1蛋白的相似结合模式。唾液HBGA-VLP结合阻断测定诱导交叉阻断效应。我们的结果表明，针对唾液HBGA的结合能力相似，并且对来自不同变体的GII.6诺如病毒株的特异性交叉阻断作用，这表明诺如病毒疫苗的开发需要更少的来自不同进化变体的GII.6菌株。
