Ma Jie, Liu Jinjin, Liu Xinyi, Wang Chao, Huo Yuqi
Center for Translational Medicine, Affiliated Infectious Diseases Hospital of Zhengzhou University (Henan Infectious Diseases Hospital, The Sixth People's Hospital of Zhengzhou), Zhengzhou, 450000, People's Republic of China.
The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, People's Republic of China.
Arch Virol. 2025 Jan 6;170(2):28. doi: 10.1007/s00705-024-06213-1.
Trypsin digestion of the GII.6 norovirus (NoV) major capsid protein VP1 promotes its binding to histo-blood group antigens (HBGAs), which are believed to be co-receptors for NoVs. In our previous study, we found that trypsin digestion led to the disassembly of GII.6 NoV virus-like particles (VLPs). In this study, we investigated the effect of trypsin digestion on the integrity of GII.6 NoV VLPs using a modified purification approach and determined the N- and C-terminal residues of the fragments produced by digestion, using peptide mass fingerprinting. We also characterized the antigenic epitopes that were affected by trypsin digestion using monoclonal antibodies (mAbs). Our results indicated that GII.6 VLPs remained intact even after complete cleavage at the P1-1/P2 junction. Most of the mAbs in supernatants of hybridoma cell clones showed reduced binding to trypsin-digested GII.6 VLPs. Eight mAbs that showed reduced binding to digested GII.6 VP1 were produced, and these were found primarily to recognize residues located in the P domain. Our results provide evidence of flexibility and extensive morphological changes in the antigenic epitope of GII.6 VLPs after trypsin digestion. It remains to be investigated whether this phenomenon also occurs in virions.
用胰蛋白酶消化GII.6型诺如病毒（NoV）的主要衣壳蛋白VP1可促进其与组织血型抗原（HBGA）结合，HBGA被认为是NoV的共同受体。在我们之前的研究中，我们发现胰蛋白酶消化会导致GII.6型NoV病毒样颗粒（VLP）的解体。在本研究中，我们使用改良的纯化方法研究了胰蛋白酶消化对GII.6型NoV VLP完整性的影响，并通过肽质量指纹图谱确定了消化产生的片段的N端和C端残基。我们还使用单克隆抗体（mAb）对受胰蛋白酶消化影响的抗原表位进行了表征。我们的结果表明，即使在P1-1/P2连接处完全裂解后，GII.6型VLP仍保持完整。杂交瘤细胞克隆上清液中的大多数mAb与经胰蛋白酶消化的GII.6型VLP的结合减少。产生了8种与消化后的GII.6型VP1结合减少的mAb，发现这些mAb主要识别位于P结构域的残基。我们的结果提供了证据，证明胰蛋白酶消化后GII.6型VLP抗原表位具有灵活性和广泛的形态变化。这种现象是否也发生在病毒体中还有待研究。
