Department of Vaccinology, Smorodintsev Research Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, Russia.
Institute of Bioengineering, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia.
PLoS One. 2018 Aug 23;13(8):e0201429. doi: 10.1371/journal.pone.0201429. eCollection 2018.
Influenza infection could be more effectively controlled if a multi-purpose vaccine with the ability to induce responses against most, or all, influenza A subtypes could be generated. Conserved viral proteins are a promising basis for the creation of a broadly protective vaccine. In the present study, the immunogenicity and protective properties of three recombinant proteins (vaccine candidates), comprising conserved viral proteins fused with bacterial flagellin, were compared.
Balb/c mice were immunized intranasally with recombinant proteins comprising either one viral protein (the ectodomain of the M2 protein, 'M2e') or two viral proteins (M2e and the hemagglutinin second subunit 'HA2' epitope) genetically fused with flagellin. Further, two different consensus variants of HA2 were used. Therefore, three experimental positives were used in addition to the negative control (Flg-his). The mucosal, humoral, and T-cell immune responses to these constructs were evaluated.
We have demonstrated that insertion of the HA2 consensus polypeptide (aa 76-130), derived from either the first (HA2-1) or second (HA2-2) virus phylogenetic group, into the recombinant Flg4M2e protein significantly enhanced its immunogenicity and protective properties. Intranasal administration of the vaccine candidates (Flg-HA2-2-4M2e or Flg-HA2-1-4M2e) induced considerable mucosal and systemic responses directed at both the M2e-protein and, in general, the influenza A virus. However, the immune response elicited by the Flg-HA2-1-4M2e protein was weaker than the one generated by Flg-HA2-2-4M2e. These recombinant proteins containing both viral peptides provide complete protection from lethal challenge with various influenza viruses: A/H3N2; A/H2N2; and A/H5N1.
This study demonstrates that the intranasal administration of Flg-HA2-2-4M2e recombinant protein induces a strong immune response which provides broad protection against various influenza viruses. This construct is therefore a strong candidate for development as a universal vaccine.
如果能研发出一种多用途疫苗，使其能够诱导针对大多数或所有甲型流感亚型的反应，那么流感感染就能得到更有效的控制。保守的病毒蛋白是创造广泛保护性疫苗的有前途的基础。在本研究中，比较了三种包含保守病毒蛋白与细菌鞭毛蛋白融合的重组蛋白（候选疫苗）的免疫原性和保护特性。
用包含一种病毒蛋白（M2 蛋白的胞外域，“M2e”）或两种病毒蛋白（M2e 和血凝素第二亚基“HA2”表位）与鞭毛蛋白基因融合的重组蛋白经鼻腔免疫 Balb/c 小鼠。此外，还使用了两种不同的 HA2 共识变体。因此，除了阴性对照（Flg-his）外，还使用了三个实验阳性。评估了这些构建物的黏膜、体液和 T 细胞免疫反应。
我们已经证明，将来自第一（HA2-1）或第二（HA2-2）病毒系统发育群的 HA2 共识多肽（aa76-130）插入重组 Flg4M2e 蛋白中，显著增强了其免疫原性和保护特性。候选疫苗（Flg-HA2-2-4M2e 或 Flg-HA2-1-4M2e）的鼻腔给药诱导了针对 M2e 蛋白和一般甲型流感病毒的大量黏膜和系统反应。然而，Flg-HA2-1-4M2e 蛋白引起的免疫应答弱于 Flg-HA2-2-4M2e 蛋白。这些包含两种病毒肽的重组蛋白提供了针对各种流感病毒（A/H3N2；A/H2N2；A/H5N1）致死性挑战的完全保护。
本研究表明，鼻腔给予 Flg-HA2-2-4M2e 重组蛋白可诱导强烈的免疫应答，对各种流感病毒提供广泛保护。因此，该构建体是作为通用疫苗开发的有力候选物。
