Bifunctional CD4-DC-SIGN Fusion Proteins Demonstrate Enhanced Avidity to gp120 and Inhibit HIV-1 Infection and Dissemination
Bifunctional CD4-DC-SIGN Fusion Proteins Demonstrate Enhanced Avidity to gp120 and Inhibit HIV-1 Infection and Dissemination
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DOI：
10.1128/aac.00623-12
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发表时间：
2012-09-01
影响因子：
4.9
通讯作者：
Hu, Qinxue
中科院分区：
文献类型：
--
作者：
Du, Tao;Hu, Kai;Hu, Qinxue
粘膜感染的早期阶段是HIV-1预防的潜在目标。CD 4是HIV-1感染的主要受体，而DC-SIGN可能在HIV-1传播中起重要作用，特别是在性传播期间。为了检验同时靶向gp 120上的CD 4和DC-SIGN结合位点的抑制剂可以提供有效的抗HIV策略的假设，我们通过将细胞外CD 4和DC-SIGN结构域与CD 4、DC-SIGN和接头的长度的不同排列融合在一起来设计构建体。我们表达、纯化并鉴定了一系列可溶性CD 4-linker-DC-SIGN（CLD）融合蛋白。分子相互作用分析表明，几个CLD，包括一个较长的接头和一个额外的颈部结构域的DC-SIGN，增强了对gp 120的亲和力。此外，这种CLD对实验室适应的和原代HIV-1分离株表现出显著增强的中和活性。此外，CLD通过DC-SIGN表达细胞系和原代人树突状细胞有效抑制HIV-1感染。人类宫颈移植模型的结果进一步加强了这一点，表明CLD有效地预防了局部和播散性感染。这是可溶性DC-SIGN双功能蛋白首次证明抗HIV的效力。我们的研究提供了一个概念的证据，即靶向gp 120上的CD 4和DC-SIGN结合位点代表了一种新的抗病毒策略。鉴于DC-SIGN与gp 120的结合增加了CD 4结合位点的暴露，并且CD 4和DC-SIGN的可溶形式在体内发生，CLD的进一步改善可能使其在预防或治疗中潜在有用。
Early stages of mucosal infection are potential targets for HIV-1 prevention. CD4 is the primary receptor in HIV-1 infection whereas DC-SIGN likely plays an important role in HIV-1 dissemination, particularly during sexual transmission. To test the hypothesis that an inhibitor simultaneously targeting both CD4 and DC-SIGN binding sites on gp120 may provide a potent anti-HIV strategy, we designed constructs by fusing the extracellular CD4 and DC-SIGN domains together with varied arrangements of the lengths of CD4, DC-SIGN and the linker. We expressed, purified and characterized a series of soluble CD4-linker-DC-SIGN (CLD) fusion proteins. Several CLDs, composed of a longer linker and an extra neck domain of DC-SIGN, had enhanced affinity for gp120 as evidenced by molecular-interaction analysis. Furthermore, such CLDs exhibited significantly enhanced neutralization activity against both laboratory-adapted and primary HIV-1 isolates. Moreover, CLDs efficiently inhibited HIV-1 infection in trans via a DC-SIGN-expressing cell line and primary human dendritic cells. This was further strengthened by the results from the human cervical explant model, showing that CLDs potently prevented both localized and disseminated infections. This is the first time that soluble DC-SIGN-based bifunctional proteins have demonstrated anti-HIV potency. Our study provides proof of the concept that targeting both CD4 and DC-SIGN binding sites on gp120 represents a novel antiviral strategy. Given that DC-SIGN binding to gp120 increases exposure of the CD4 binding site and that the soluble forms of CD4 and DC-SIGN occur in vivo, further improvement of CLDs may render them potentially useful in prophylaxis or therapeutics.