自2013年3月，我国首次报道了H7N9流感病毒感染人以来，H7N9流感病毒已经经历了5波流行，感染病例1562例（截至2017年9月13日），死亡率达30%。H7N9流感病毒不仅具有潜在大流行的威胁，也对养禽业造成了巨大的损失。与其他流感病毒一样，H7N9流感病毒变异十分迅速，已经形成了多个基因型，因此研制具有广谱交叉保护效果的H7N9流感病毒疫苗十分必要。
H7N9 HA蛋白的结构设计与表达纯化
该团队之前的研究证实了H3亚型HA蛋白跨膜区（Transmembrane domain, TM）与HA蛋白稳定性、HA蛋白交叉免疫原性关系密切，通过HA跨膜区置换策略可以提高三聚化H1、H5和H9亚型HA蛋白的亚型间交叉保护力。在H7N9广谱疫苗的研究中，该团队也已经证明具有跨膜区置换的重组H7N9流感病毒相对于野生型重组H7N9流感病毒具有更好的交叉免疫原性和交叉保护力。本文证明将H7N9流感病毒HA蛋白TM置换为H3亚型HA TM，并通过昆虫杆状病毒表达系统表达出包含TM置换的重组H7N9 HA蛋白。在小鼠模型中，重组HA蛋白制备的亚单位疫苗能够诱导机体产生针对不同分支毒株抗原的更高的HI抗体、HA特异的IgG抗体、HA特异的IFN-γ细胞因子。并且该疫苗能够对小鼠同源或异源H7N9病毒攻毒提供完全保护，经过免疫的小鼠在攻毒后无明显肺部病变和炎症反应。
王洋博士为本文第一作者，曹永长教授为本文通讯作者。
曹永长教授团队长期进行动物病毒学研究，先后获得国家自然科学基金、863项目、国家重点研发计划项目、广东省自然科学基金等科研项目的资助，发表SCI论文50余篇。目前该团队致力于流感病毒防控、冠状病毒（猪流行性腹泻病毒PEDV、鸡传染性支气管炎病毒IBV）遗传演化和免疫逃逸机制研究，已获得多项研究成果。
Recombinant influenza H7 hemagglutinin containing CFLLC minidomain in the transmembrane domain showed enhanced cross-protection in mice
Abstract
Since February 2013, H7N9 influenza virus, causing human infections with high mortality in China, has been a potential pandemic threat. The H7N9 viruses are found to diverge into distinct genotypes as other influenza viruses; thus a vaccine that can provide sufficient cross-protection against different genotypes of H7N9 viruses is urgently needed. Ourprevious studies demonstrated that the HA-based structural design approach by introducing a CFLLC minidomain into transmembrane domain (TM) of H1, H5 or H9 hemagglutinin (HA) proteins by replacing with H3 subtype HA TM could enhance their cross-protection. In this study, we used Sf9 insect cell expression system to express recombinant H7 HA proteins H7-53WT, in which HA gene was derived from H7N9-53 strain, and H7-53TM containing CFLLC minidomian by replacing its TM domain with H3 HA TM. We investigated whether introduction of CFLLC minidomain into H7 HA (H7-53TM) could increase its cross-reactivity and cross-protection against different genotypes of H7N9 viruses. The results showed that the H7-53TM either with or without squalene adjuvantinduced increased HI antibodies, serum IgG antibodies, and IFN-γ production to a panel of 7 H7N9 viruses in mice.Vaccinated animals with H7-53TM alone showed complete protection against challenge with heterologous H7N9-MCX strain, while H7-53WT alone showed incomplete protection (80%). Furthermore, mice vaccinated with H7-53TM HA showed less body weight loss and less pulmonary lesions and inflammation after challenge with homologous or heterologous H7N9 viruses, comparing to H7-53WT. In summary, this study presents a better subunit vaccine candidate (H7-53TM) against potential H7N9 pandemic.
文章链接：
https://www.ncbi.nlm.nih.gov/pubmed/28912070