HIV Variation in Injection Drug Users: Mapping Broadly Neutralizing Antibodies

描述(由申请人提供)：拟议的研究利用从注射吸毒者(IDU)收集的病毒来解决艾滋病毒疫苗研究的两个高度优先的研究目标。这些是：1)确定中和不同初级分离株的抗体的特异性，以及2)确定为什么广泛中和抗体不常见以及如何激发它们。在约10%-30%的HIV-1感染者(HIV+血清)的血清中发现了能够中和多种HIV临床分离株的广谱中和抗体(BNAbs)。然而，尽管经过多年的研究，bNAbs识别的表位仍然没有明确的定义。在这项提案中，我们将我们实验室最近开发的一种新方法--群体分析应用于从泰国曼谷注射吸毒者(IDU)获得的一组独特的临床标本。这些研究的结果应该使我们第一次能够绘制HIV+血清中bNAbs识别的表位图，并识别影响中和敏感性和抵抗力的突变。我们已经在初步研究中证明了这种方法的可行性，并用它来鉴定gp41中的一个新突变，该突变赋予了对bNAbs中和的敏感性。这一信息将有助于开发新的抗原，旨在诱导类似于HIV+血清中的bNAb。艾滋病毒在注射吸毒者中传播的特殊情况，即不同基因的个体群体通过共用针头感染相同的病毒(注射吸毒者传播队列)，提供了一个独特的机会，使从群体分析中收集的信息最大化，并更好地确定成功的艾滋病毒疫苗的性能要求。两种HIV：E(A/E重组)和B‘在泰国人群中共同循环的事实使我们能够专注于具有广泛、跨分支中和活性的bNAbs。以前识别由bNAbs识别的表位的努力依赖于产生单抗。然而，经过20多年的努力，只有少数具有广泛中和活性的单抗被鉴定出来。此外，这些单抗的生理相关性仍然不确定，因为很难证明艾滋病毒感染者产生具有类似特异性的抗体。我们的新表位映射方法利用发生在每个艾滋病毒感染者体内的密切相关的病毒变异群体作为可用于映射表位的自然发生突变的来源。这种方法通过专注于在艾滋病毒感染的正常过程中进化的抗体和病毒突变来减轻人们对生理相关性的担忧。拟议的研究为艾滋病毒疫苗的开发提供了一种独特的、循序渐进的方法。

DESCRIPTION (provided by applicant): The proposed studies make use of viruses collected from injection drug users (IDUs) to address two high priority research objectives for HIV vaccine research. These are: 1) Defining the specificities of antibodies that neutralize diverse primary isolates, and 2) Determining why broadly neutralizing antibodies are uncommon and how they can be elicited. Broadly neutralizing antibodies (bNAbs) able to neutralize a wide range of clinical isolates of HIV are found in sera from ~10-30% of HIV-1 infected individuals (HIV+ sera). However, despite years of investigation, the epitopes recognized by bNAbs remain poorly defined. In this proposal, we apply a new method, swarm analysis, recently developed in our lab, to a unique set of clinical specimens obtained from injection drug users (IDUs) in Bangkok, Thailand. The results from these studies should allow us for the first time to map the epitopes recognized by bNAbs in HIV+ sera, and to identify mutations that affect sensitivity and resistance to neutralization. We have demonstrated the feasibility of this approach in preliminary studies, and have used it to identify a new mutation in gp41 that confers sensitivity to neutralization by bNAbs. This information will be useful for the development of novel antigens designed to elicit bNAbs similar to those found in HIV+ sera. The special circumstance of HIV transmission in IDUs, where groups of genetically diverse individuals are infected with the same virus through needle sharing (IDU transmission cohorts), provides a unique opportunity to maximize the information collected from the swarm analysis and better define the performance requirements for a successful HIV vaccine. The fact that two clades of HIV: E (A/E recombinant) and B' co-circulate in the Thai cohort allows us to focus on bNAbs with broad, cross-clade neutralizing activity. Previous efforts to identify epitopes recognized by bNAbs relied on production of monoclonal antibodies. However, after more than 20 years of effort, only a few monoclonal antibodies with potent broadly neutralizing activity have been identified. Moreover, the physiologic relevance of these monoclonal antibodies remains uncertain, since it has been difficult to demonstrate that HIV-infected humans produce antibodies with similar specificities. Our new method of epitope mapping makes use of the swarm of closely related virus variants that occur within each HIV-infected individual as a source of naturally occurring mutants that can be used to map epitopes. This method alleviates concerns regarding physiologic relevance by focusing on antibodies and virus mutants that evolve during the normal course of HIV infection. The proposed studies provide a unique, stepwise "back to the drawing board" approach to HIV vaccine development.