Defining Neutralization Breadth in HIV+ Human Serum

描述（由申请人提供）：艾滋病毒疫苗策略尚未成功地在人体中产生广泛中和的抗体反应。有限数量的广泛中和的人类抗HIV单克隆抗体已被确定，并已成为深入研究的主题。这些抗体的组合可以保护猕猴免受SIV/HIV嵌合病毒的感染，这表明如果它们可以通过接种疫苗在未感染的人类中引起，它们可以提供保护功效。然而，这些抗体在受感染的人身上可能很少见。相反，hiv感染者在血清中表现出相当大的中和广度并不罕见。我们假设在感染期间，在相当一部分个体中产生了多特异性反应，并解释了中和广度。本研究的主要目标是确定具有广泛中和抗体反应的HIV+个体血清中存在的HIV多特异性反应，并将中和抗体特异性与那些具有狭窄中和抗体广度的个体进行比较。为此，我们将首先定义包膜三聚体结合、亲和度和中和宽度之间的关系，使用一种新的基于vlp的测定方法。我们将通过抗体耗尽技术和表位定位来确定三聚体特异性抗体反应是否对多克隆血清中和的广度有实质性贡献。中和抗体反应的克隆性将由宽中和剂和窄中和剂确定。血清分析将辅以VLP结合鉴定的B细胞亚群分析，并将鉴定与宽中和和窄中和相关的表型。总之，这些研究将启发我们对中和广度的理解，并有助于设计基于中和抗体的疫苗方案。一种有效的艾滋病毒疫苗很可能需要产生中和抗体反应，以防止感染社区中流行的艾滋病毒类型。使用标准疫苗技术很难产生如此广泛的中和反应。在这个项目中，我们将研究具有广泛中和反应证据的HIV感染者的抗体反应。通过详细了解这些艾滋病毒感染者体内存在的抗体反应，我们将深入了解如何更好地设计一种可在未感染者中产生类似反应的保护性艾滋病毒疫苗。

DESCRIPTION (provided by applicant): HIV vaccine strategies have not yet succeeded in generating broadly neutralizing antibody responses in humans. A limited number of broadly neutralizing human monoclonal antibodies against HIV have been identified and have been the subject of intensive study. Combinations of such antibodies can protect macaques from infection with SIV/HIV chimeric virus, suggesting that if they could be elicited in uninfected humans through vaccination, they could provide protective efficacy. These antibodies may be rare in infected humans, however. In contrast, HIV-infected individuals who demonstrate substantial breadth of neutralization in serum are not rare. We hypothesize that a polyspecific response develops during infection in a substantial subset of individuals and accounts for neutralization breadth. The major goal of this proposal is to define the polyspecific response to HIV present in sera from HIV+ individuals with broad neutralizing antibody responses, and to compare the neutralizing antibody specificities with those who demonstrate narrow neutralization breadth. To do this, we will first define the relationship between envelope trimer binding, avidity, and breadth of neutralization using a novel VLP-based assay. We will determine if trimer-specific antibody responses contribute substantially to the breadth of neutralization in polyclonal serum through antibody depletion techniques and epitope mapping. The clonality of the neutralizing antibody response will be determined for broad and narrow neutralizers. Serum analysis will be complemented by the analysis of B cell subsets identified by VLP binding, and phenotypes associated with broad vs. narrow neutralization will be identified. Together, these studies will enlighten our understanding of neutralization breadth and contribute to the design of a neutralizing antibody-based vaccine regimen. It is very likely that an effective HIV vaccine will need to generate neutralizing antibody responses that can prevent infection with the types of HIV that are circulating in the community. It has been very difficult to generate such broad neutralizing responses using standard vaccine techniques. In this project, we will study the antibody responses in individuals who are infected with HIV who have evidence of broad neutralizing responses. By understanding in detail the antibody responses present in these HIV-infected individuals, we will gain insights into how we can better design a protective HIV vaccine that can generate similar responses in uninfected persons.