Antibody-Induced Internalization of the Human Respiratory Syncytial Virus Fusion Protein.
Antibody-Induced Internalization of the Human Respiratory Syncytial Virus Fusion Protein.
复制标题
抗体诱导的人呼吸道合胞病毒融合蛋白的内化。
DOI：
10.1128/jvi.00184-17
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发表时间：
2017
影响因子：
5.4
通讯作者：
Delputte,P
中科院分区：
文献类型：
--
作者：
Leemans,A;DeSchryver,M;VanderGucht,W;Heykers,A;Pintelon,I;Hotard,AL;Moore,ML;Melero,JA;McLellan,JS;Graham,BS;Broadbent,L;Power,UF;Caljon,G;Cos,P;Maes,L;Delputte,P
呼吸道合胞病毒（RSV）感染仍然是婴儿呼吸道疾病和住院的主要原因。感染经常复发，并建立一个弱和短暂的免疫力。迄今为止，RSV免疫预防和疫苗研究主要集中在RSV融合（F）蛋白，但疫苗仍然难以捉摸。RSV F蛋白是高度保守的表面糖蛋白，并且是由自然感染诱导的中和抗体的主要靶标。在这里，我们分析了RSV特异性抗体与感染细胞表面表达的RSV抗原结合后抗原-抗体复合物的内化过程。通过间接免疫荧光染色和流式细胞术分析，发现在加入RSV特异性多克隆抗体（PAb）或RSV糖蛋白特异性单克隆抗体（MAb）后，RSV F蛋白和附着（G）蛋白在感染和转染的细胞中内化。不同细胞系、分化良好的原代支气管上皮细胞（WD-PBEC）和RSV分离株的内化实验表明，抗体内化可被视为RSV的一般特征。更具体地，对于RSV F，内化机制显示为网格蛋白依赖性的。所有测试的RSV F靶向MAb，无论其表位如何，均诱导RSV F的内化。在不同的MAb之间没有观察到差异，表明RSV F内化是表位非依赖性的。由于这一过程可以通过影响病毒组装和生产而抗病毒，或者通过限制抗体的功效和效应器机制而对病毒有益，因此需要进一步研究以确定这种情况在体内发生的程度以及这可能如何影响RSV复制。重要的是，目前对新免疫预防和疫苗开发的研究主要集中在RSV F蛋白上，因为，除其他外，RSV F特异性抗体能够保护婴儿免受严重疾病的影响，如果给药的话。然而，自然RSV感染后建立的抗体反应对再次感染的保护作用很差，并且高水平的抗体并不总是与保护相关。因此，RSV可能能够至少部分干扰抗体诱导的中和。在本研究中，描述了表面表达的RSV F蛋白在与RSV特异性抗体相互作用后内化的过程。一方面，这种抗原-抗体复合物内化可能导致抗病毒作用，因为它可能干扰病毒颗粒形成和病毒产生。另一方面，这种机制也可能降低抗体介导的效应机制对感染细胞的功效。
Respiratory syncytial virus (RSV) infections remain a major cause of respiratory disease and hospitalizations among infants. Infection recurs frequently and establishes a weak and short-lived immunity. To date, RSV immunoprophylaxis and vaccine research is mainly focused on the RSV fusion (F) protein, but a vaccine remains elusive. The RSV F protein is a highly conserved surface glycoprotein and is the main target of neutralizing antibodies induced by natural infection. Here, we analyzed an internalization process of antigen-antibody complexes after binding of RSV-specific antibodies to RSV antigens expressed on the surface of infected cells. The RSV F protein and attachment (G) protein were found to be internalized in both infected and transfected cells after the addition of either RSV-specific polyclonal antibodies (PAbs) or RSV glycoprotein-specific monoclonal antibodies (MAbs), as determined by indirect immunofluorescence staining and flow-cytometric analysis. Internalization experiments with different cell lines, well-differentiated primary bronchial epithelial cells (WD-PBECs), and RSV isolates suggest that antibody internalization can be considered a general feature of RSV. More specifically for RSV F, the mechanism of internalization was shown to be clathrin dependent. All RSV F-targeted MAbs tested, regardless of their epitopes, induced internalization of RSV F. No differences could be observed between the different MAbs, indicating that RSV F internalization was epitope independent. Since this process can be either antiviral, by affecting virus assembly and production, or beneficial for the virus, by limiting the efficacy of antibodies and effector mechanism, further research is required to determine the extent to which this occursin vivoand how this might impact RSV replication.IMPORTANCECurrent research into the development of new immunoprophylaxis and vaccines is mainly focused on the RSV F protein since, among others, RSV F-specific antibodies are able to protect infants from severe disease, if administered prophylactically. However, antibody responses established after natural RSV infections are poorly protective against reinfection, and high levels of antibodies do not always correlate with protection. Therefore, RSV might be capable of interfering, at least partially, with antibody-induced neutralization. In this study, a process through which surface-expressed RSV F proteins are internalized after interaction with RSV-specific antibodies is described. One the one hand, this antigen-antibody complex internalization could result in an antiviral effect, since it may interfere with virus particle formation and virus production. On the other hand, this mechanism may also reduce the efficacy of antibody-mediated effector mechanisms toward infected cells.