Antigenicity and immunogenicity of HIV-1 gp140 with different combinations of glycan mutation and V1/V2 region or V3 crown deletion
Antigenicity and immunogenicity of HIV-1 gp140 with different combinations of glycan mutation and V1/V2 region or V3 crown deletion
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具有不同聚糖突变和V1/V2区或V3冠缺失组合的HIV-1 gp140的抗原性和免疫原性
DOI：
10.1016/j.vaccine.2019.09.073
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发表时间：
2019-12-03
期刊：
影响因子：
5.5
通讯作者：
Hu, Qinxue
中科院分区：
文献类型：
--
作者：
Fu, Ming;Hu, Kai;Hu, Qinxue
HIV-1包膜糖蛋白（Env）上的碳水化合物部分起到屏蔽保守中和表位的作用，而高免疫原性可变区在诱导非中和抗体方面具有免疫优势，这是使用Env作为疫苗候选物诱导广泛中和抗体（bNAbs）的主要挑战。在这项研究中，我们设计了一系列的HIV-1 gp140构建物，去除N276/N463聚糖，删除V1/V2区域和V3冠，单独或联合。我们首先证明了所有的结构具有相当的表达水平，并且主要以三聚体的形式表达。从哺乳动物细胞中纯化gp140后，我们在体外检测了它们与bNAbs和非naabs的结合以及在体内诱导bNAbs的能力。抗体结合实验显示，去除N276/N463聚糖并缺失V1/V2区域，gp140与靶向cd4结合位点的bNAbs VRC01和3BNC117，以及靶向cd4诱导的非naabs A32、17b和F425 a18的结合增强。而gp140突变体V3冠的进一步缺失则显示其与这些抗体的结合能力略有降低。免疫原性研究表明，上述突变并未通过小鼠DNA-DNA或dna -蛋白启动-增强策略诱导更高的env特异性IgG反应，而中和实验也未显示野生型和突变的gp140之间存在明显差异。综上所示，我们的研究结果表明，去除N276/N463的聚糖和删除V1/V2区域可以暴露cd4结合位点和cd4诱导的表位，但单独暴露似乎不能增强小鼠对bNAbs的诱导，这表明需要额外的修饰或/和免疫策略。此外，我们建立的gp140蛋白的生产策略以及gp140的抗原性和免疫原性分析为进一步的疫苗设计和评估提供了有用的手段。(C) 2019 Elsevier Ltd.版权所有。
The carbohydrate moieties on HIV-1 envelope glycoprotein (Env) act as shields to mask conserved neutralizing epitopes, while the hyperimmunogenic variable regions are immunodominant in inducing non-neutralizing antibodies, representing the major challenge for using Env as a vaccine candidate to induce broadly neutralizing antibodies (bNAbs). In this study, we designed a series of HIV-1 gp140 constructs with the removal of N276/N463 glycans, deletion of the V1/V2 region and the V3 crown, alone or in combination. We first demonstrated that all the constructs had a comparable level of expression and were mainly expressed as trimers. Following purification of gp140s from mammalian cells, we measured their binding to bNAbs and non-NAbs in vitro and capability in inducing bNAbs in vivo. Antibody binding assay showed that removal of N276/N463 glycans together with the deletion of V1/V2 region enhanced the binding of gp140s to CD4-binding site-targeting bNAbs VRC01 and 3BNC117, and CD4-induced epitopes-targeting non-NAbs A32, 17b and F425 A1g8, whereas further deletion of V3 crown in the gp140 mutants demonstrated slightly compromised binding capability to these Abs. Immunogenicity study showed that the above mutations did not lead to the induction of a higher Env-specific IgG response via either DNA-DNA or DNA-protein prime-boost strategies in mice, while neutralization assay did not show an apparent difference between wild type and mutated gp140s. Taken together, our results indicate that removal of glycans at N276/N463 and deletion of the V1/V2 region can expose the CD4-binding site and CD4-induced epitopes, but such exposure alone appears incapable of enhancing the induction of bNAbs in mice, informing that additional modification or/and immunization strategies are needed. In addition, the strategies which we established for producing gp140 proteins and for analyzing the antigenicity and immunogenicity of gp140 provide useful means for further vaccine design and assessment. (C) 2019 Elsevier Ltd. All rights reserved.