H1N1、H3N2亚型流感病毒Mosaic-HA1的表达及对小鼠的免疫原性评价

Expression of influenza A H1N1 and H3N2 viruses Mosaic-HA1 antigens and evaluation of its immunogenicity in mice

摘要:

流感病毒给全球公共卫生带来了严重威胁，疫苗接种是预防流感及严重并发症的有效手段。本研究分析了北半球2012–2022年间人类甲型流感病毒(influenza A virus, IAV)流行株血凝素(hemagglutinin, HA)中HA1亚基的氨基酸突变趋势和抗原显性位点变化情况。基于世界卫生组织(World Health Organization, WHO)公布的2022年北半球流感疫苗推荐株A/Wisconsin/588/2019 (H1N1)和A/Darwin/6/2021 (H3N2)的HA1氨基酸序列，通过马赛克(mosaic)遗传算法设计了3种Mosaic-HA1抗原并将其在293F细胞中进行表达、纯化。将纯化后的Mosaic-HA1抗原与明矾佐剂以1:1的体积比混合制备亚单位疫苗并免疫BALB/c小鼠以评价免疫效果。酶联免疫吸附实验表明Mosaic-HA1抗原能产生同时结合两种亚型HA1的IgG，其中结合H3蛋白、H1蛋白的特异性效价IgG效价分别达到10⁵、10³以上，攻毒实验表明Mosaic-HA1能抵抗H3N2和H1N1流行毒株的攻击。本研究通过对不同亚型IAV毒株HA1中免疫显性位点进行重新组合，为多价亚单位流感疫苗开发提供了新思路。

Abstract:

Vaccination is the most effective measure for reducing and preventing influenza and related complications. In this study, we analyzed the mutation trend and the antigen dominant site changes of the amino acid sequence of hemagglutinin subunit 1 (HA1) of human influenza A virus (IAV) in the northern hemisphere from 2012 to 2022. According to the HA1 sequences of A/Darwin/6/2021 (H3N2) and A/Wisconsin/588/2019 (H1N1) recommended by the World Health Organization in the 2022 influenza season in northern hemisphere, we employed the mosaic algorithm to design three Mosaic-HA1 antigens through stepwise substitution. Mosaic-HA1 was expressed and purified in 293F cells and then mixed with the alum adjuvant at a volume ratio of 1:1. The mixture was used to immunize BALB/c mice, and the immunogenicity was evaluated. Enzyme-linked immunosorbent assay showed that Mosaic-HA1 induced the production of IgG targeting two types of HA1, the specific IgG titers for binding to H3 protein and H1 protein reached 10⁵ and 10³respectively. The challenge test showed that Mosaic-HA1 protected mice from H3N2 or H1N1. This study designs the vaccines by recombination of major antigenic sites in different subtypes of IAV, giving new insights into the development of multivalent subunit vaccines against influenza.