Hemagglutinin 1-specific immunoglobulin G and Fab molecules mediate postattachment neutralization of influenza A virus by inhibition of an early fusion event
Hemagglutinin 1-specific immunoglobulin G and Fab molecules mediate postattachment neutralization of influenza A virus by inhibition of an early fusion event
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DOI：
10.1128/jvi.75.21.10208-10218.2001
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发表时间：
2001-11-01
影响因子：
5.4
通讯作者：
Dimmock, NJ
中科院分区：
文献类型：
--
作者：
Edwards, MJ;Dimmock, NJ
在标准中和（STAN）中，病毒和抗体在接种靶细胞之前一起反应，并且病毒和细胞早期相互作用中几乎任何相关过程的抑制，包括病毒附着到细胞受体的抑制，都可能是特定单克隆抗体（MAb）中和的原因。为了简化对抗体作用的解释，我们进行了附着后中和（PAN）的研究，其中在引入中和抗体之前允许病毒附着到靶细胞上。我们使用流感病毒A/PR/8/34（H1N1）和单克隆免疫球蛋白G（IgG）分子及其对血凝素1（HA 1）蛋白的抗原位点Sb（尖端）、Ca 2（环）和Cb（铰链）具有特异性的Fab。所有IgG和Fab都给出PAN，尽管与STAN相比效率降低。因此，抗体的二价结合对于PAN不是必需的。根据定义，这些单克隆抗体中没有一种通过抑制病毒附着而产生PAN，并且它们不将附着的病毒从靶细胞上清除或抑制病毒的内吞作用。然而，如R18荧光去猝灭或红细胞溶血所示，病毒-细胞融合与中和成正比并以剂量依赖性方式受到抑制，因此可能是观察到的中和的原因。然而，为了获得PAN，有必要抑制融合前中间体的活化，这是融合途径上已知的最早形式，当病毒在pH 5和4 ℃下孵育时产生。PAN抗体可以通过结合与细胞接触的HA三聚体和/或紧邻病毒-细胞接触点的三聚体起作用，从而抑制额外受体-HA复合物的募集。
In standard neutralization (STAN), virus and antibody are reacted together before inoculation of target cells, and inhibition of almost any of the processes concerned in the early interaction of virus and cell, including inhibition of virus attachment to cell receptors, can be the cause of neutralization by a particular monoclonal antibody (MAb). To simplify the interpretation of antibody action, we carried out a study of postattachment neutralization (PAN), where virus is allowed to attach to target cells before neutralizing antibody is introduced. We used influenza virus A/PR/8/34 (H1N1) and monoclonal immunoglobulin G (IgG) molecules and their Fabs specific to antigenic sites Sb (tip), Ca2 (loop), and Cb (hinge) of the hemagglutinin 1 (HA1) protein. All IgGs and Fabs gave PAN, although with reduced efficiency compared with STAN. Thus, bivalent binding of antibody was not essential for PAN. By definition, none of these MAbs gave PAN by inhibiting virus attachment, and they did not elute attached virus from the target cell or inhibit endocytosis of virus. However, virus-cell fusion, as demonstrated by R18 fluorescence dequenching or hemolysis of red blood cells, was inhibited in direct proportion to neutralization and in a dose-dependent manner and was thus likely to be responsible for the observed neutralization. However, to get PAN, it was necessary to inhibit the activation of the prefusion intermediate, the earliest known form on the fusion pathway that is created when virus is incubated at pH 5 and 4 degreesC. PAN antibodies may act by binding HA trimers in contact with the cell and/or trimers in the immediate vicinity of the virus-cell contact point and so inhibit the recruitment of additional receptor-HA, complexes.