表現與純化新型H7N9流感病毒血球凝集素球狀頭部以製備鼠源單株抗體

Abstract

於2013年3月底在中國上海和安徽兩地首次發現新型H7N9流感病毒感染人的病例，且其病發期短、重症率與死亡率均高而引起高度關注。同年4月台灣亦出現首例境外移入病例，並從檢體中驗出具有克流感抗藥性的H7N9病毒株。根據世界衛生組織WHO統計，截至2016年5月23日全球共累計786例病例，其中307例死亡，死亡率高達39%。遺傳學的分析顯示此新型H7N9病毒株已逐漸適應哺乳類的宿主，因此研發疫苗與快速檢驗及治療所需之抗體迫切重要。 本研究主要利用大腸桿菌表現系統及昆蟲細胞表現系統生產新型H7N9病毒之血球凝集素 (Hemagglutinin, HA) 的球狀頭部HA1，以提供基礎科學研究、疫苗與抗體的研發。目前已成功表現及量產岀HA1重組蛋白，經免疫小鼠後都能成功引起免疫反應，並順利取得能抑制雞血球凝集的多株抗體，尤其以昆蟲細胞表現系統所生產的HA1，其免疫效果更佳。此外，本研究也成功製備出抗H7N9 HA1之單株抗體，此單株抗體亦具有抑制雞血球凝集的能力，且將其稀釋至256,000倍時，仍可利用免疫染色法偵測岀HA1抗原。未來將以本研究之基礎與成果，進行快篩平台與次單位疫苗之研發工作。

The novel H7N9 influenza virus emerged in March 2013 in China and continues to cause sporadic human infections. In April 2013, Taiwan CDC reported the first imported case of H7N9 infection from China, and the H7N9 virus variants isolated from this patient display Tamiflu resistance. As of May 23, 2016, the World Health Organization (WHO) had reported 783 human infections and 306 deaths with mortality rates approaching 38%. Based on genetic analysis, this novel H7N9 virus shows some extent adaptation to mammalian hosts. Therefore, it is very important to develop rapid laboratory diagnostics, antibodies and subunit vaccines for better pandemic preparedness. This study focused on production of the globular head domain of H7N9 hemagglutinin (HA) by using E. coli expression system and baculovirus expression system for generation of antibodies. The HA1 proteins expressed in E. coli and Sf21 insect cells can induce strong immune response in mice. The purified HA1 proteins were applied for immunization of BALB/c mice to produce polyclonal and monoclonal antibodies. The monoclonal antibody generated in the present study shows high specificity to H7N9 HA1 and also has great ability for inhibiting hemagglutination of chicken red blood cells. The HA1 proteins and the specific mAb are useful tools for furthermore developing laboratory diagnostic platform and subunit vaccine candidates in the future.