Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE) Molecular and Virology Unit VIM-Unité Mixte de Recherche (UMR) 892, University Paris-Saclay, Jouy-en-Josas, France.
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE) Unité Mixte de Recherche (UMR1225), Interactions Hótes-Agents Pathogénes-Ecole Nationale Vétérinaire de Toulouse (IHAP-ENVT)-University of Toulouse, Toulouse, France.
Front Immunol. 2021 Nov 11;12:772550. doi: 10.3389/fimmu.2021.772550. eCollection 2021.
Current inactivated vaccines against influenza A viruses (IAV) mainly induce immune responses against highly variable epitopes across strains and are mostly delivered parenterally, limiting the development of an effective mucosal immunity. In this study, we evaluated the potential of intranasal formulations incorporating conserved IAV epitopes, namely the long alpha helix (LAH) of the stalk domain of hemagglutinin and three tandem repeats of the ectodomain of the matrix protein 2 (3M2e), as universal mucosal anti-IAV vaccines in mice and chickens. The IAV epitopes were grafted to nanorings, a novel platform technology for mucosal vaccination formed by the nucleoprotein (N) of the respiratory syncytial virus, in fusion or not with the C-terminal end of the P97 protein (P97c), a recently identified Toll-like receptor 5 agonist. Fusion of LAH to nanorings boosted the generation of LAH-specific systemic and local antibody responses as well as cellular immunity in mice, whereas the carrier effect of nanorings was less pronounced towards 3M2e. Mice vaccinated with chimeric nanorings bearing IAV epitopes in fusion with P97c presented modest LAH- or M2e-specific IgG titers in serum and were unable to generate a mucosal humoral response. In contrast, N-3M2e or N-LAH nanorings admixed with Montanide™ gel (MG) triggered strong specific humoral responses, composed of serum type 1/type 2 IgG and mucosal IgG and IgA, as well as cellular responses dominated by type 1/type 17 cytokine profiles. All mice vaccinated with the [N-3M2e + N-LAH + MG] formulation survived an H1N1 challenge and the combination of both N-3M2e and N-LAH nanorings with MG enhanced the clinical and/or virological protective potential of the preparation in comparison to individual nanorings. Chickens vaccinated parenterally or mucosally with N-LAH and N-3M2e nanorings admixed with Montanide™ adjuvants developed a specific systemic humoral response, which nonetheless failed to confer protection against heterosubtypic challenge with a highly pathogenic H5N8 strain. Thus, while the combination of N-LAH and N-3M2e nanorings with Montanide™ adjuvants shows promise as a universal mucosal anti-IAV vaccine in the mouse model, further experiments have to be conducted to extend its efficacy to poultry.
目前针对甲型流感病毒（IAV）的灭活疫苗主要诱导针对不同株间高度变异表位的免疫应答，且主要通过注射给药，限制了有效黏膜免疫的产生。在这项研究中，我们评估了将包含保守 IAV 表位的鼻内制剂（即血凝素茎部的长α螺旋（LAH）和基质蛋白 2 的三个串联重复的外域（3M2e））作为通用黏膜抗 IAV 疫苗在小鼠和鸡中的潜力。将 IAV 表位嫁接于纳米环上，纳米环是一种由呼吸道合胞病毒核蛋白（N）形成的新型黏膜疫苗接种平台技术，与最近发现的 Toll 样受体 5 激动剂 P97 蛋白（P97c）的 C 端融合或不融合。LAH 与纳米环融合增强了 LAH 特异性全身和局部抗体应答以及细胞免疫应答，而纳米环对 3M2e 的载体效应不明显。用融合有 P97c 的嵌合纳米环免疫的小鼠在血清中产生适度的 LAH 或 M2e 特异性 IgG 滴度，并且无法产生黏膜体液反应。相比之下，N-3M2e 或 N-LAH 纳米环与 Montanide™凝胶（MG）混合可引发强烈的特异性体液反应，由血清 1/2 型 IgG 和黏膜 IgG 和 IgA 组成，以及以 1/17 型细胞因子为主的细胞反应。所有用[N-3M2e + N-LAH + MG]制剂免疫的小鼠在 H1N1 攻毒后存活，与单独的 N-3M2e 和 N-LAH 纳米环相比，N-3M2e 和 N-LAH 纳米环与 MG 的组合增强了制剂的临床和/或病毒学保护潜力。用 N-LAH 和 N-3M2e 纳米环与 Montanide™佐剂经粘膜或肌内接种的鸡产生了特异性全身体液反应，但未能赋予其对高致病性 H5N8 株异源亚型攻毒的保护。因此，虽然 N-LAH 和 N-3M2e 纳米环与 Montanide™佐剂的组合在小鼠模型中显示出作为通用黏膜抗 IAV 疫苗的潜力，但需要进一步实验将其功效扩展到家禽。
