Elicitation of Neutralizing Antibodies Directed against CD4-Induced Epitope(s) Using a CD4 Mimetic Cross-Linked to a HIV-1 Envelope Glycoprotein
Elicitation of Neutralizing Antibodies Directed against CD4-Induced Epitope(s) Using a CD4 Mimetic Cross-Linked to a HIV-1 Envelope Glycoprotein
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DOI：
10.1371/journal.pone.0030233
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发表时间：
2012-01-24
期刊：
影响因子：
3.7
通讯作者：
Barnett, Susan W.
中科院分区：
文献类型：
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作者：
Dey, Antu K.;Burke, Brian;Barnett, Susan W.
能够产生广泛中和抗体 (BNAb) 的 HIV-1 包膜糖蛋白 (Env) 结构的鉴定对于成功开发针对 HIV-1 的疫苗（旨在引发有效的体液免疫反应）至关重要。为此，生产新的 Env 结构至关重要，该结构可能通过呈现保守表位（否则会被封闭）来诱导 BNAb。在这里，我们关注的是一种将 Env 稳定在代表其主要 (CD4) 受体结合状态的构象的结构，从而暴露出高度保守的“CD4 诱导”(CD4i) 表位，已知这些表位对于辅助受体结合和随后的病毒感染很重要。生产了一种 CD4 模拟微型蛋白 miniCD4 (M64U1-SH)，并使用位点特异性二硫键与重组三聚体 gp140 包膜糖蛋白 (gp140) 共价复合。由此产生的 gp140-miniCD4 (gp140-S-S-M64U1) 复合物被 CD4i 抗体和 HIV-1 共受体 CCR5 识别。对兔子进行免疫后，与单独的 gp140 蛋白相比，gp140-miniCD4 复合物引发了最高滴度的 CD4i 结合抗体以及增强的针对 1 级病毒的中和抗体。针对 HIV-2(7312/V434M) 的中和和额外的血清图谱证实了针对 CD4i 表位的抗体的特异性引发。这些结果证明了基于结构的方法在改善针对特定区域（例如此处的 CD4i 表位）的免疫原性反应方面的效用，及其在疫苗应用中的潜在作用。
The identification of HIV-1 envelope glycoprotein (Env) structures that can generate broadly neutralizing antibodies (BNAbs) is pivotal to the development of a successful vaccine against HIV-1 aimed at eliciting effective humoral immune responses. To that end, the production of novel Env structure(s) that might induce BNAbs by presentation of conserved epitopes, which are otherwise occluded, is critical. Here, we focus on a structure that stabilizes Env in a conformation representative of its primary (CD4) receptor-bound state, thereby exposing highly conserved "CD4 induced" (CD4i) epitope(s) known to be important for co-receptor binding and subsequent virus infection. A CD4-mimetic miniprotein, miniCD4 (M64U1-SH), was produced and covalently complexed to recombinant, trimeric gp140 envelope glycoprotein (gp140) using site-specific disulfide linkages. The resulting gp140-miniCD4 (gp140-S-S-M64U1) complex was recognized by CD4i antibodies and the HIV-1 co-receptor, CCR5. The gp140-miniCD4 complex elicited the highest titers of CD4i binding antibodies as well as enhanced neutralizing antibodies against Tier 1 viruses as compared to gp140 protein alone following immunization of rabbits. Neutralization against HIV-2(7312/V434M) and additional serum mapping confirm the specific elicitation of antibodies directed to the CD4i epitope(s). These results demonstrate the utility of structure-based approach in improving immunogenic response against specific region, such as the CD4i epitope(s) here, and its potential role in vaccine application.