Modified HIV envelope proteins with enhanced binding to neutralizing monoclonal antibodies
Modified HIV envelope proteins with enhanced binding to neutralizing monoclonal antibodies
复制标题
DOI：
10.1016/j.virol.2004.10.005
复制
发表时间：
2005-01-05
期刊：
影响因子：
3.7
通讯作者：
Compans, RW
中科院分区：
文献类型：
--
作者：
Kang, SM;Quan, FS;Compans, RW
针对人类免疫缺陷病毒（HIV）的中和抗体的靶标是天然病毒体上的三聚体Env蛋白。受体结合位点的保守中和表位位于Env蛋白的凹陷核心中，部分被糖基化和可变环掩蔽。在这项研究中，我们研究了通过糖基化位点突变、可变环缺失或两种类型突变的组合修饰HIV Env蛋白质的影响，以确定其蛋白质功能和与中和抗体的反应性。修饰的Env蛋白在昆虫或哺乳动物细胞中表达，并通过流式细胞术测定其与表位特异性广泛中和单克隆抗体（Mab）的反应性。一种独特的突变体命名为3G，在CD 4结合位点周围的V3/C3结构域内的三个糖基化基序中具有突变，在昆虫和哺乳动物表达系统中均显示出与最广泛中和的Mab（b12和2F 5）的更高水平的结合。与野生型对照相比，缺失V1和V2环结构域或具有两种类型突变的独特组合的突变体也以更高水平与大多数中和Mab结合。除了具有可变环缺失和去糖基化突变的组合的突变体之外，大多数突变体保持与CD 4结合并以与野生型Env蛋白相似或更高的水平诱导合胞体形成的能力。我们的研究表明，在CD 4结合位点周围的结构域或可变环缺失突变体中糖基化降低的修饰的HIV Env蛋白以比野生型更高的水平暴露重要的中和表位，并可能提供新的疫苗免疫原。(C)2004年爱思唯尔公司All rights reserved.
The target for neutralizing antibodies against human immunodeficiency virus (HIV) is the trimeric Env protein oil the native virion. Conserved neutralizing epitopes of receptor binding sites are located in the recessed core of the Env protein, partially masked by glycosylations and variable loops. In this study, we have investigated the effects of modifications of the HIV Env protein by glycosylation site mutations, deletions of variable loops, or combinations of both types of mutations oil their protein functions and reactivities with neutralizing antibodies. Modified Env proteins were expressed in insect or mammalian cells, and their reactivity with epitope-specific broadly neutralizing monoclonal antibodies (Mabs) was determined by flow cytometry. A unique mutant designated 3G with mutations in three glycosylation motifs within the V3/C3 domains surrounding the CD4 binding site showed higher levels of binding to most broadly neutralizing Mabs (b12 and 2F5) in both insect and mammalian expression systems. Mutants with a deletion of both V1 and V2 loop domains or with a unique combination of both types of mutations also bound to most neutralizing Mabs at higher levels compared to the wild-type control. Most mutants maintained the ability to bind CD4 and to induce syncytium formation at similar or higher levels as compared to that of the wild-type Env protein, except for a mutant with a combination of variable loop deletions and deglycosylation mutations. Our study suggests that modified HIV Env proteins with reduced glycosylation in domains surrounding the CD4 binding site or variable loop-deleted mutants expose important neutralizing epitopes at higher levels than wild type and may provide novel vaccine immunogens. (C) 2004 Elsevier Inc. All rights reserved.