HIV Vaccines Based on GP120-CD4 Mimetic Complexes

基于 GP120-CD4 模拟复合物的 HIV 疫苗

• 批准号: 7334749
• 负责人: Anthony L DeVico
• 金额: $ 34.53万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 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 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7334749
• 关键词: Adjuvant; Affinity; Affinity Chromatography; Agreement; Animals; Antibodies; Antibody Formation; Antigens; Binding; Biological Assay; Cellular Immunity; Closure; Complex; Condition; Development; Docking; Dose; Epidemic; General Population; Genetic; Goals; HIV; HIV Antibodies; HIV Envelope Protein gp120; HIV vaccine; Human; Immune Sera; Infection; Lead; Link; Macaca; Modeling; Modification; Oryctolagus cuniculus; Peptides; Property; Structure; Subunit Vaccines; Vaccines; Virus; base; computer generated; crosslink; design; immunogenicity; improved; mimetics; neutralizing antibody; prevent; prophylactic; protein aminoacid sequence; research study; response; transmission process; vaccine development

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）：停止HIV流行的最终手段是一种预防性疫苗，可阻止一般人群中的病毒传播。现在可以接受的是，这种疫苗将不得不引起抗HIV抗体反应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，该免疫原将引起能够防止（中和）受到全世界原发性艾滋病毒菌株（中和）感染的广泛中和抗体。 我们的方法着重于CD4结合引起的GP120的“约束”过渡状态结构。在先前的研究中，我们表明，猕猴中的交联gp120溶剂CD4复合物在猕猴中引起抗体，这些抗体中和各种主分离株，无论进化枝如何。我们还表明，这些“广泛中和”抗体是通过亲和力色谱分离出的，具有约束的单链复合物（称为SCBAL/M9），其中包含与CD4模拟微动蛋白相关的GP120（CD4M9）。因此，单链GP120-CD4模拟复合物值得探索，因为疫苗亚基免疫原子会引起人类中和抗体的广泛中和抗体。但是，在初步实验中，SC/M9比单个链GP120-CD4复合物（FLSC）更有效地引起了广泛中和抗体。这可能意味着SCBAL/M9的很大一部分无法在稳态条件下保持内部相互作用，因此并未呈现GP120上的关键约束决定因素，而这些决定因素是引起广泛中和抗体所需的。这种不稳定性与CD4M9的已知特性一致，CD4M9的结合亲和力仅为CD4的1％。同意，我们的初步研究表明，SCBAL/M9中分子内相互作用的稳定性不如FLSC。因此，我们将在该项目中评估的中心假设是，我们将通过序列修饰来提高SCBAL/M9的免疫原性，从而产生高度稳定的分子内复合物。为了探讨这一假设，该项目的目标1将是设计和评估SCBAL/M9的修改版本，以改善内部结合稳定性。 AIM 2将是比较兔子中修饰复合物与SCBAL/M9的免疫原性。将进行结合和功能测定，以验证任何修饰的免疫原子都不会引起与人或兔子CD4交叉反应的抗体。我们预计这些努力将产生新的候选免疫原子，这些免疫原子可用于在多种疫苗环境中引起广泛中和抗体。