Chemical Cross-Linking Stabilizes Native-Like HIV-1 Envelope Glycoprotein Trimer Antigens.
Chemical Cross-Linking Stabilizes Native-Like HIV-1 Envelope Glycoprotein Trimer Antigens.
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化学交联稳定了天然样的HIV-1包膜糖蛋白三聚体抗原。
DOI：
10.1128/jvi.01942-15
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发表时间：
2016-01-15
影响因子：
5.4
通讯作者：
Sattentau QJ
中科院分区：
文献类型：
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作者：
Schiffner T;de Val N;Russell RA;de Taeye SW;de la Peña AT;Ozorowski G;Kim HJ;Nieusma T;Brod F;Cupo A;Sanders RW;Moore JP;Ward AB;Sattentau QJ
HIV-1包膜糖蛋白（Env）三聚体的主要中和抗体免疫逃避策略包括构象和结构不稳定性。稳定的可溶性三聚体如BG 505 SOSIP. 664模拟病毒体相关Env的结构，但仍然采样不同的构象状态。在这里，我们证明了用戊二醛或异双功能交联剂处理BG 505 SOSIP.664三聚体引入了额外的稳定性，对抗原性的影响相对较小。因此，大多数广泛中和抗体（bNAb）表位交联后保留，而最弱或非中和抗体（非NAb）的结合减少。交联稳定了混合群体中存在的所有Env构象异构体，并且可以通过bNAb亲和色谱分离单个构象异构体。使用四级表位特异性bNAb PGT 145、PGT 151和3BC 315的交联构象异构体的阳性选择和使用针对V3区的非NAb的阴性选择都富集了三聚体群体，具有改善的bNAb抗原性。使用进化枝B B41 SOSIP.664三聚体获得了类似的结果。因此，交联方法可用于对抗一些HIV-1 Env蛋白的天然构象异质性，并且通过外推，也可用于对抗来自其他病原体的疫苗免疫原。重要性开发一种疫苗来诱导针对HIV-1的保护性抗体具有首要的公共卫生重要性。免疫原设计的最新进展提供了具有接近天然形态和抗原性的可溶性重组包膜糖蛋白三聚体。然而，这些三聚体在构象上是柔性的，潜在地降低中和抗体表位的B细胞识别。在这里，我们表明，化学交联增加三聚体的稳定性，减少非中和抗体的结合，同时在很大程度上保持中和抗体的结合。交联后，通过阳性或阴性抗体亲和力选择个别稳定的构象变体进一步改善了三聚体的抗原性和形态学特征。这种方法可以普遍适用于HIV-1 Env，也适用于其他构象灵活的病原体抗原。
Major neutralizing antibody immune evasion strategies of the HIV-1 envelope glycoprotein (Env) trimer include conformational and structural instability. Stabilized soluble trimers such as BG505 SOSIP.664 mimic the structure of virion-associated Env but nevertheless sample different conformational states. Here we demonstrate that treating BG505 SOSIP.664 trimers with glutaraldehyde or a heterobifunctional cross-linker introduces additional stability with relatively modest effects on antigenicity. Thus, most broadly neutralizing antibody (bNAb) epitopes were preserved after cross-linking, whereas the binding of most weakly or nonneutralizing antibodies (non-NAb) was reduced. Cross-linking stabilized all Env conformers present within a mixed population, and individual conformers could be isolated by bNAb affinity chromatography. Both positive selection of cross-linked conformers using the quaternary epitope-specific bNAbs PGT145, PGT151, and 3BC315 and negative selection with non-NAbs against the V3 region enriched for trimer populations with improved antigenicity for bNAbs. Similar results were obtained using the clade B B41 SOSIP.664 trimer. The cross-linking method may, therefore, be useful for countering the natural conformational heterogeneity of some HIV-1 Env proteins and, by extrapolation, also vaccine immunogens from other pathogens. IMPORTANCE The development of a vaccine to induce protective antibodies against HIV-1 is of primary public health importance. Recent advances in immunogen design have provided soluble recombinant envelope glycoprotein trimers with near-native morphology and antigenicity. However, these trimers are conformationally flexible, potentially reducing B-cell recognition of neutralizing antibody epitopes. Here we show that chemical cross-linking increases trimer stability, reducing binding of nonneutralizing antibodies while largely maintaining neutralizing antibody binding. Cross-linking followed by positive or negative antibody affinity selection of individual stable conformational variants further improved the antigenic and morphological characteristics of the trimers. This approach may be generally applicable to HIV-1 Env and also to other conformationally flexible pathogen antigens.