Job E R, Schotsaert M, Ibañez L I, Smet A, Ysenbaert T, Roose K, Dai M, de Haan C A M, Kleanthous H, Vogel T U, Saelens X
VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium.
Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
J Virol. 2018 Jan 30;92(4). doi: 10.1128/JVI.01584-17. Print 2018 Feb 15.
There is increasing evidence to suggest that antibodies directed toward influenza A virus (IAV) neuraminidase (NA) are an important correlate of protection against influenza in humans. Moreover, the potential of NA-specific antibodies to provide broader protection than conventional hemagglutinin (HA) antibodies has been recognized. Here, we describe the isolation of two monoclonal antibodies, N1-7D3 and N1-C4, directed toward the N1 NA. N1-7D3 binds to a conserved linear epitope in the membrane-distal, carboxy-terminal part of the NA and reacted with the NA of seasonal H1N1 isolates ranging from 1977 to 2007 and the 2009 H1N1pdm virus, as well as A/Vietnam/1194/04 (H5N1). However, N1-7D3 lacked NA inhibition (NI) activity and the ability to protect BALB/c mice against a lethal challenge with a range of H1N1 viruses. Conversely, N1-C4 bound to a conformational epitope that is conserved between two influenza virus subtypes, 2009 H1N1pdm and H5N1 IAV, and displayed potent antiviral activity mediating both NI and plaque size reduction. Moreover, N1-C4 could provide heterosubtypic protection in BALB/c mice against a lethal challenge with 2009 H1N1pdm or H5N1 virus. Glutamic acid residue 311 in the NA was found to be critical for the NA binding and antiviral activity of monoclonal antibody N1-C4. Our data provide further evidence for cross-protective epitopes within the N1 subtype and highlight the potential of NA as an important target for vaccine and therapeutic approaches. Influenza remains a worldwide burden on public health. As such, the development of novel vaccines and therapeutics against influenza virus is crucial. Human challenge studies have recently highlighted the importance of antibodies directed toward the viral neuraminidase (NA) as an important correlate of reduced influenza-associated disease severity. Furthermore, there is evidence that anti-NA antibodies can provide broader protection than antibodies toward the viral hemagglutinin. Here, we describe the isolation and detailed characterization of two N1 NA-specific monoclonal antibodies. One of these monoclonal antibodies broadly binds N1-type NAs, and the second displays NA inhibition and and antiviral activity against 2009 H1N1pdm and H5N1 influenza viruses. These two new anti-NA antibodies contribute to our understanding of the antigenic properties and protective potential of the influenza virus NA antigen.
越来越多的证据表明，针对甲型流感病毒（IAV）神经氨酸酶（NA）的抗体是人类预防流感的重要保护相关因素。此外，NA特异性抗体比传统血凝素（HA）抗体提供更广泛保护的潜力已得到认可。在此，我们描述了两种针对N1 NA的单克隆抗体N1-7D3和N1-C4的分离。N1-7D3与NA膜远端羧基末端部分的一个保守线性表位结合，并与1977年至2007年的季节性H1N1分离株、2009年甲型H1N1流感大流行病毒以及A/越南/1194/04（H5N1）的NA发生反应。然而，N1-7D3缺乏NA抑制（NI）活性以及保护BALB/c小鼠免受一系列H1N1病毒致死性攻击的能力。相反，N1-C4与2009年甲型H1N1流感大流行病毒和H5N1 IAV这两种流感病毒亚型之间保守的构象表位结合，并表现出强大的抗病毒活性，介导NI和噬斑大小减小。此外，N1-C4可在BALB/c小鼠中提供针对2009年甲型H1N1流感大流行病毒或H5N1病毒致死性攻击的异源亚型保护。发现NA中的谷氨酸残基311对于单克隆抗体N1-C4的NA结合和抗病毒活性至关重要。我们的数据为N1亚型内的交叉保护表位提供了进一步证据，并突出了NA作为疫苗和治疗方法重要靶点的潜力。流感仍然是全球公共卫生的负担。因此，开发新型抗流感病毒疫苗和疗法至关重要。人体激发研究最近强调了针对病毒神经氨酸酶（NA）的抗体作为降低流感相关疾病严重程度的重要保护相关因素的重要性。此外，有证据表明抗NA抗体比针对病毒血凝素的抗体能提供更广泛的保护。在此，我们描述了两种N1 NA特异性单克隆抗体的分离和详细表征。其中一种单克隆抗体广泛结合N1型NA，另一种对2009年甲型H1N1流感大流行病毒和H5N1流感病毒表现出NA抑制和抗病毒活性。这两种新的抗NA抗体有助于我们理解流感病毒NA抗原的抗原特性和保护潜力。
