Liang Bing, Fan Menglu, Meng Qi, Zhang Yaping, Jin Jiayu, Chen Na, Lu Yuanlu, Jiang Chenfeng, Zhang Xingxing, Zou Zongyou, Ping Jihui, Su Juan
MOE International Joint Collaborative Research Laboratory for Animal Health and Food Safety and Jiangsu Engineering Laboratory of Animal Immunology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute in CAAS, Harbin, China.
Transbound Emerg Dis. 2024 May 17;2024:6641285. doi: 10.1155/2024/6641285. eCollection 2024.
As the H9N2 subtype avian influenza virus (H9N2 AIV) evolves naturally, mutations in the hemagglutinin (HA) protein still occur, which involves some sites with glycosylations. It is widely established that glycosylation of the H9N2 AIV HA protein has a major impact on the antigenicity and pathogenicity of the virus. However, the biological implications of a particular glycosylation modification site (GMS) have not been well investigated. In this study, we generated viruses with different GMSs based on wild-type (WT) viruses. Antigenicity studies revealed that the presence of viruses with a 200G/295G mutation (with glycosylation at position 200 and deletion of glycosylation at position 295 in the HA protein) combined with a single GMS, such as 87G, 127G, 148G, 178G, or 265G, could significantly affect the antigenicity of the virus. Pathogenicity assays revealed that the addition of GMS, such as 127G, 188G, 148G, 178G, or 54G, decreased the virulence of the virus in mice, except for 87G. The removal of GMS, such as 280G or 295G, increased the pathogenicity of the virus in mice. Further studies on pathogenicity revealed that 87G/295G could also enhance the pathogenicity of the virus. Finally, we selected the WT, WT-87G, WT-295G, and WT-87G/295G strains as our further research targets to investigate the detailed biological properties of the viruses. GMS, which can enhance viral pathogenicity, did not significantly affect replication or viral stability but significantly promoted the expression of proinflammatory factors to enhance inflammatory responses in mouse lungs. These findings further deepen our understanding of the influence of the glycosylation of the HA protein of H9N2 AIV on the pathogenicity and antigenicity of the virus in mice.
随着H9N2亚型禽流感病毒（H9N2 AIV）自然进化，血凝素（HA）蛋白仍会发生突变，其中涉及一些存在糖基化的位点。普遍认为，H9N2 AIV HA蛋白的糖基化对病毒的抗原性和致病性有重大影响。然而，特定糖基化修饰位点（GMS）的生物学意义尚未得到充分研究。在本研究中，我们基于野生型（WT）病毒构建了具有不同GMS的病毒。抗原性研究表明，具有200G/295G突变（HA蛋白中第200位存在糖基化且第295位糖基化缺失）并结合单个GMS（如87G、127G、148G、178G或265G）的病毒的存在，可显著影响病毒的抗原性。致病性试验表明，添加GMS（如127G、188G、148G、178G或54G）会降低病毒在小鼠中的毒力，但87G除外。去除GMS（如280G或295G）会增加病毒在小鼠中的致病性。对致病性的进一步研究表明，87G/295G也可增强病毒的致病性。最后，我们选择WT、WT-87G、WT-295G和WT-87G/295G毒株作为进一步的研究对象，以研究病毒的详细生物学特性。能够增强病毒致病性的GMS对病毒复制或稳定性没有显著影响，但能显著促进促炎因子的表达，从而增强小鼠肺部的炎症反应。这些发现进一步加深了我们对H9N2 AIV HA蛋白糖基化对病毒在小鼠中的致病性和抗原性影响的理解。
