The Sir William Dunn School of Pathology, Oxford, United Kingdom.
J Virol. 2013 Sep;87(18):10163-72. doi: 10.1128/JVI.01161-13. Epub 2013 Jul 10.
Experimental vaccine antigens based upon the HIV-1 envelope glycoproteins (Env) have failed to induce neutralizing antibodies (NAbs) against the majority of circulating viral strains as a result of antibody evasion mechanisms, including amino acid variability and conformational instability. A potential vaccine design strategy is to stabilize Env, thereby focusing antibody responses on constitutively exposed, conserved surfaces, such as the CD4 binding site (CD4bs). Here, we show that a largely trimeric form of soluble Env can be stably cross-linked with glutaraldehyde (GLA) without global modification of antigenicity. Cross-linking largely conserved binding of all potent broadly neutralizing antibodies (bNAbs) tested, including CD4bs-specific VRC01 and HJ16, but reduced binding of several non- or weakly neutralizing antibodies and soluble CD4 (sCD4). Adjuvanted administration of cross-linked or unmodified gp140 to rabbits generated indistinguishable total gp140-specific serum IgG binding titers. However, sera from animals receiving cross-linked gp140 showed significantly increased CD4bs-specific antibody binding compared to animals receiving unmodified gp140. Moreover, peptide mapping of sera from animals receiving cross-linked gp140 revealed increased binding to gp120 C1 and V1V2 regions. Finally, neutralization titers were significantly elevated in sera from animals receiving cross-linked gp140 rather than unmodified gp140. We conclude that cross-linking favors antigen stability, imparts antigenic modifications that selectively refocus antibody specificity and improves induction of NAbs, and might be a useful strategy for future vaccine design.
实验性的 HIV-1 包膜糖蛋白(Env)疫苗抗原未能诱导针对大多数循环病毒株的中和抗体(NAb),这是由于抗体逃逸机制,包括氨基酸变异性和构象不稳定性。一种潜在的疫苗设计策略是稳定 Env,从而将抗体反应集中在固有暴露的保守表面上,如 CD4 结合位点(CD4bs)。在这里,我们表明,可稳定交联戊二醛(GLA)的可溶性 Env 的大部分三聚体形式而不改变抗原性的全局修饰。交联主要保留了所有测试的有效广谱中和抗体(bNAb)的结合,包括 CD4bs 特异性的 VRC01 和 HJ16,但降低了几种非中和或弱中和抗体和可溶性 CD4(sCD4)的结合。交联或未修饰的 gp140 与佐剂一起给予兔子,产生可区分的总 gp140 特异性血清 IgG 结合滴度。然而,接受交联 gp140 的动物的血清显示出与接受未修饰 gp140 的动物相比,CD4bs 特异性抗体结合明显增加。此外,接受交联 gp140 的动物的血清的肽图谱显示与 gp120 C1 和 V1V2 区域的结合增加。最后,接受交联 gp140 的动物的血清中的中和滴度明显升高,而不是未修饰的 gp140。我们得出结论,交联有利于抗原稳定性,赋予抗原修饰,选择性地重新聚焦抗体特异性,并改善 NAb 的诱导,可能是未来疫苗设计的有用策略。
N Engl J Med. 2013-2-7
J AIDS Clin Res. 2012
Nat Biotechnol. 2012-9