HIV Vaccines Based on GP120-CD4 Mimetic Complexes

基于 GP120-CD4 模拟复合物的 HIV 疫苗

• 批准号: 7039242
• 负责人: Anthony L DeVico
• 金额: $ 48万
• 依托单位: UNIVERSITY OF MD BIOTECHNOLOGY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7039242
• 关键词: AIDS education /prevention; AIDS therapy; AIDS vaccines; HIV envelope protein gp120; T lymphocyte; affinity chromatography; antigen antibody reaction; biomimetics; biotechnology; cellular immunity; laboratory rabbit; neutralizing antibody; vaccine development; vaccine evaluation

DESCRIPTION (provided by applicant): The ultimate means for stopping the HIV epidemic is a prophylactic vaccine that blocks virus transmission in the general population. It is now accepted that such a vaccine will have to elicit anti-HIV antibody responses as well as cellular immunity to provide protection. To meet this goal, it is necessary to identify an immunogen that will elicit broadly neutralizing antibodies capable of preventing (neutralizing) infection by primary HIV strains found worldwide. Our approach focuses on the "constrained" transition state structure of gp120 induced by CD4 binding. In previous studies, we showed that crosslinked gp120-soluble CD4 complexes elicited antibodies in macaques that neutralized a wide variety of primary isolates regardless of Clade. We also showed that these "broadly neutralizing" antibodies were isolated from immune sera by affinity chromatography with a constrained single chain complex (called SCBaL/M9) containing gp120 linked to a CD4 mimetic miniprotein (CD4M9). Thus, single chain gp120-CD4 mimetic complexes warrant exploration as vaccine subunit immunogens to elicit broadly neutralizing antibodies in humans. However, in preliminary experiments SCBaL/M9 elicited broadly neutralizing antibodies less efficiently than a single chain gp120-CD4 complex (FLSC). This could mean that a significant portion of SCBaL/M9 fails to maintain an intrachain interaction under steady state conditions and consequently does not present the key constrained determinants on gp120 that are needed to elicit broadly neutralizing antibodies. Such instability is consistent with the known properties of CD4M9, which has a binding affinity for gp120 that is only about 1% that of CD4. In agreement, our preliminary studies show that the intramolecular interactions in SCBaL/M9 are less stable than in FLSC. Accordingly, our central hypothesis, which we will evaluate in this project, is that we will improve the immunogenicity of SCBaL/M9 by sequence modifications that produce highly stabilized intramolecular complexes. In order to explore this hypothesis, Aim 1 of this project will be to design and evaluate modified versions of SCBaL/M9 for improved intrachain binding stability. Aim 2 will be to compare the immunogenicity of modified complexes versus SCBaL/M9 in rabbits. Binding and functional assays will be performed to verify that none of the modified immunogens elicits antibodies that crossreactive with human or rabbit CD4. We expect these efforts to yield new candidate immunogens that can be feasibly used to elicit broadly neutralizing antibodies in a variety of vaccine contexts.

描述（由申请人提供）：阻止HIV流行的最终手段是阻止病毒在一般人群中传播的预防性疫苗。现在公认的是，这种疫苗必须引起抗HIV抗体应答以及细胞免疫以提供保护。为了实现这一目标，有必要确定一种免疫原，该免疫原将引发能够预防（中和）世界各地发现的主要HIV毒株感染的广泛中和抗体。 我们的方法侧重于“约束”的过渡态结构的gp 120诱导的CD 4结合。在以前的研究中，我们表明，交联的gp 120可溶性CD 4复合物在猕猴中引起抗体，中和各种各样的主要分离株，无论进化枝。我们还表明，这些“广泛中和”抗体是从免疫血清中分离的亲和层析与约束性单链复合物（称为SCBaL/M9）含有连接到一个CD 4模拟微蛋白（CD 4 M9）的gp 120。因此，单链gp 120-CD 4模拟物复合物值得探索作为疫苗亚单位免疫原，以在人体中引发广泛的中和抗体。然而，在初步实验中，SCBaL/M9引起的广泛中和抗体的效率低于单链gp 120-CD 4复合物（FLSC）。这可能意味着SCBaL/M9的很大一部分在稳态条件下不能维持链内相互作用，因此不能在gp 120上呈现引发广泛中和抗体所需的关键限制性决定簇。这种不稳定性与CD 4 M9的已知特性一致，其对gp 120的结合亲和力仅为CD 4的约1%。与此一致，我们的初步研究表明，SCBaL/M9中的分子内相互作用不如FLSC中的稳定。因此，我们将在本项目中评估的中心假设是，我们将通过产生高度稳定的分子内复合物的序列修饰来改善SCBaL/M9的免疫原性。为了探索这一假设，本项目的目标1将是设计和评估SCBaL/M9的修饰版本，以改善链内结合稳定性。目的2是比较修饰复合物与SCBaL/M9在兔中的免疫原性。将进行结合和功能测定，以验证经修饰的免疫原均不激发与人或兔CD 4交叉反应的抗体。我们期望这些努力能够产生新的候选免疫原，这些免疫原可以在各种疫苗背景下可行地用于引发广泛中和抗体。