HIV Variation in Injection Drug Users: Mapping Broadly Neutralizing Antibodies

描述（由申请方提供）：拟定的研究使用从注射吸毒者（IDUs）中收集的病毒，以解决HIV疫苗研究的两个高优先级研究目标。这些措施是：1）确定中和不同的初级分离株的抗体的特异性，2）确定为什么广泛中和抗体是罕见的，以及如何引起它们。在约10-30%的HIV-1感染个体（HIV+血清）的血清中发现了能够中和多种HIV临床分离株的广泛中和抗体（bNAb）。然而，尽管经过多年的研究，bNAb识别的表位仍然定义不清。在这个建议中，我们应用一种新的方法，群体分析，最近在我们的实验室，一套独特的临床标本从注射吸毒者（IDUs）在泰国曼谷。这些研究的结果应该使我们能够首次绘制出HIV+血清中bNAb识别的表位，并确定影响中和敏感性和抗性的突变。我们已经在初步研究中证明了这种方法的可行性，并使用它来鉴定gp 41中的新突变，该突变赋予对bNAbs中和的敏感性。这些信息将有助于开发新的抗原，旨在引发类似于HIV+血清中发现的bNAb。注射吸毒者中艾滋病毒传播的特殊情况，即遗传多样性个体群体通过共用针头感染同一病毒（注射吸毒者传播队列），为最大限度地利用从群体分析中收集的信息和更好地确定成功的艾滋病毒疫苗的性能要求提供了一个独特的机会。HIV的两个进化枝：E（A/E重组体）和B'在泰国群体中共循环的事实允许我们关注具有广泛的、跨进化枝中和活性的bNAb。先前鉴定bNAb识别的表位的努力依赖于单克隆抗体的产生。然而，经过20多年的努力，只有少数具有有效的广泛中和活性的单克隆抗体已被确定。此外，这些单克隆抗体的生理相关性仍然不确定，因为很难证明HIV感染的人产生具有相似特异性的抗体。我们的新表位作图方法利用了每个HIV感染者体内出现的密切相关的病毒变体群，作为可用于绘制表位的天然突变体的来源。这种方法通过关注在HIV感染的正常过程中进化的抗体和病毒突变体来消除对生理相关性的关注。拟议的研究为HIV疫苗开发提供了一种独特的、逐步的“回到绘图板”方法。公共卫生相关性：拟议的研究将分析来自注射吸毒者的病毒，以收集有关病毒变异和广泛中和抗体反应特异性的基本信息。这些结果对于开发有效的艾滋病毒疫苗非常重要。

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. PUBLIC HEALTH RELEVANCE: The proposed studies will analyze viruses from injection drug users to collect basic information on virus variation and the specificity of broadly neutralizing antibody responses. The results are important for the development of an effective HIV vaccine.