Antibodies Recognizing Quaternary Differences in HIV Envelope Glycoproteins (K08)

描述（由申请方提供）：识别仅在功能性HIV三聚体包膜上可见的独特构象表位的抗体（Ab）被认为对HIV中和很重要，并且可能是包膜（Env）病毒序列选择压力的关键决定因素。我们已经从来自HIV阳性受试者的单细胞分选B细胞产生了一组候选Env三聚体特异性Ab。我建议的工作，以确定重要的抗体结构的决定因素识别艾滋病毒三聚体的Env，并在这样做，提供设计一个有效的艾滋病毒疫苗的见解。我假设Env三聚体特异性Ab而不是Env单体特异性Ab的持续亲和力成熟是HIV感染期间Env序列多样性的主要驱动力。我将研究这些新的天然人抗体序列克隆到Fab和全长抗体表达系统。然后，我将使用这些结构来定义中和抗体的生化和结构特征。在具体目标1中，1将比较Env单体反应性Ab与Env三聚体特异性Ab的结合和中和特征。1将使用表面等离子体共振来比较结合和可感染的报告物TZM-bl细胞系来评估中和。我们期望显示Env三聚体特异性Ab比Env单体反应性Ab更有效地结合和中和。在具体目标2，1中，将确定结合动力学和中和效力与体细胞超突变的关系。根据我的假设和初步数据，具有大量突变的Ab可能是通过亲和力成熟过程产生的，因此，其结合和中和能力得到改善。有趣的是，大多数观察到的突变发生在抗体结合的主要决定因素CDR 3环之外。具体目标3旨在定义CDR 3环外的体细胞突变在HIV中和中的作用。将通过定点诱变产生诱变Ab与种系Ab序列的杂交体。我将比较天然抗体与这些杂合抗体的结合和中和。由于突变的程度，我们期望显示出CDR 3环以外的区域，特别是重链框架3，在HIV中和中的关键作用。 相关性：这项工作的总体目标是改进疫苗的设计，以产生更高效力的艾滋病毒抗体。这项工作将直接研究在HIV感染过程中形成的天然抗体，以发现它们如何结合病毒。这不仅有助于提高我们对免疫系统如何对艾滋病毒作出反应的认识，而且还有助于我们了解如何改进艾滋病毒疫苗和其他疫苗的成分，以提高其效力。

DESCRIPTION (provided by applicant): Antibodies (Abs) recognizing unique conformational epitopes only seen on functional HIV trimeric envelope are thought to be important for HIV neutralization and may be the key determinant of selection pressure on envelope (Env) viral sequences. We have created a panel of candidate Env trimer-specific Abs from single-cell sorting B cells from HIV positive subjects. I propose work to define important Ab structural determinants necessary for recognition of HIV trimeric Env and, in doing so, to provide insights for design of an effective HIV vaccine. I hypothesize that continued affinity maturation of Env trimer-specific Abs, rather than Env monomer- specific Abs, is the principal driving force for Env sequence diversity during HIV infection. I will study these novel native human Ab sequences by cloning them into Fab and full-length Ab expression systems. I will then use these constructs to define the biochemical and structural features of neutralizing Abs. In specific aim 1,1 will compare the binding and neutralization characteristics of Env monomer-reactive Abs to Env trimer-specific Abs. 1 will use surface plasmon resonance to compare binding and the infectible reporter TZM-bl cell line to assess neutralization. We expect to show the Env trimer-specific Abs bind and neutralize more effectively than Env monomer-reactive Abs. In specific aim 2,1 will determine the relationship of binding kinetics and neutralization potency to somatic hypermutation. It follows from my hypothesis and preliminary data that Abs possessing large numbers of mutations are likely being created by the process of affinity maturation, and hence, are improved in their binding and neutralization capabilities. Interestingly, most of the observed mutations occur outside of the major determinant of Abs binding, the CDR3 loop. Specific aim 3 is designed to define the role of somatic mutation outside of the CDR3 loop in HIV neutralization. Hybrids of mutagenized Abs with germline Ab sequences will be created by site-directed mutagenesis. I will compare binding and neutralization of the native Abs to these hybrid Abs. Because of the extent of mutation, we expect to show a critical role for regions outside of the CDR3 loop, particularly heavy chain framework 3, in HIV neutralization. RELEVANCE: The overall aim of this work is improvement in design of vaccines to produce higher potency antibodies against HIV. This work will directly study natural antiodies formed during HIV infection to find how they bind virus. Not only may this help improve our knowledge of how the immune system reacts to HIV, but it may shed light on how we can improve components of HIV vaccines and other vaccines to increase their potency.