Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA.
Department of Pediatrics, Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA; Children's Healthcare of Atlanta, Atlanta, GA, USA.
Vaccine. 2019 Oct 16;37(44):6656-6664. doi: 10.1016/j.vaccine.2019.09.041. Epub 2019 Sep 18.
Pre-fusion stabilizing mutations (DS-Cav1) in soluble fusion (F) proteins of human respiratory syncytial virus (RSV) were previously reported. Here we investigated the antigenic and immunogenic properties of pre-fusion like RSV F proteins on enveloped virus-like particles (VLP). Additional mutations were introduced to DS-Cav1 (F-dcmTM VLP); fusion peptide deletion and cleavage mutation site 1 (F1d-dcmTM VLP) or both sites (F12d-dcmTM VLP). F1d-dcmTM VLP and F12d-dcmTM VLP displayed higher reactivity against pre-fusion specific site Ø and antigenic site I and II specific monoclonal antibodies, compared to F-dcmTM VLP with DS-Cav1 only. Mice immunized with F1d-dcmTM VLP and F12d-dcmTM VLP induced higher levels of DS-Cav1 pre-fusion specific IgG antibodies, RSV neutralizing activity titers, and effective lung viral clearance after challenge. These results suggest that cleavage site mutations and fusion peptide deletion in addition to DS-Cav1 mutations have contributed to structural stabilization of pre-fusion like F conformation on enveloped VLP, capable of inducing high levels of pre-fusion F specific and RSV neutralizing antibodies.
先前已有报道称，人类呼吸道合胞病毒（RSV）可溶性融合（F）蛋白中的预融合稳定突变（DS-Cav1）。在此，我们研究了包膜病毒样颗粒（VLP）上类似预融合的 RSV F 蛋白的抗原和免疫原性特性。对 DS-Cav1（F-dcmTM VLP）进行了额外的突变引入；融合肽缺失和切割突变位点 1（F1d-dcmTM VLP）或两个位点（F12d-dcmTM VLP）。与仅具有 DS-Cav1 的 F-dcmTM VLP 相比，F1d-dcmTM VLP 和 F12d-dcmTM VLP 对预融合特异性位点 Ø 和抗原性位点 I 和 II 特异性单克隆抗体表现出更高的反应性。用 F1d-dcmTM VLP 和 F12d-dcmTM VLP 免疫的小鼠在挑战后诱导了更高水平的 DS-Cav1 预融合特异性 IgG 抗体、RSV 中和活性滴度和有效的肺部病毒清除。这些结果表明，除了 DS-Cav1 突变外，切割位点突变和融合肽缺失有助于包膜 VLP 上类似预融合的 F 构象的结构稳定，能够诱导高水平的预融合 F 特异性和 RSV 中和抗体。
