Glycan dependent epitopes of HIV broadly neutralizing antibodies

描述（由申请人提供）：尽管全世界许多组织共同努力生产一种有效的艾滋病毒疫苗，但目前还没有有效的疫苗。疫苗的靶点是包膜刺突蛋白（gp 120/gp 41），它介导与CD 4 T细胞表面受体的结合。从疫苗的角度来看，问题是刺突蛋白是高度糖基化的，具有多达25个或更多的N-连接聚糖，形成了一个“聚糖盾牌”，阻止了对潜在蛋白质的免疫反应。然而，许多HIV感染个体产生靶向密集聚糖阵列的广泛中和抗体（bnAb）。对这些聚糖依赖性bnAb的分析表明，它们与刺突蛋白上的不同区域结合，并且它们识别不同类型的聚糖。特别地，一些抗体对未加工的“高甘露糖”型聚糖表现出高特异性，而其他抗体对更高度加工的“复杂型”聚糖表现出特异性。目前知识的一个主要差距是什么类型的聚糖存在于完整病毒上gp 120/gp 41上的每个糖基化位点。这是了解聚糖依赖性bnAb的最佳表位的关键信息。在这个项目中，我们寻求更好地定义聚糖依赖性bnAb的表位，并利用这些信息开发免疫原，引发靶向聚糖盾的中和免疫应答。我们将使用一种新的糖蛋白质组学方法来分析和确定实验室细胞系和外周血单核细胞中产生的HIV病毒gp 120/gp 41上每个糖基化位点的聚糖类型（高甘露糖或复合物）。我们将利用这些信息来生产合成支架，这些支架携带用于表征bnAb的最佳表位的定义聚糖，并产生与完整病毒上gp 120的糖基化近似的重组gp 120免疫原。将检测合成支架和糖基化优化的重组gp 120三聚体对聚糖依赖性gp 120抗体介导的中和免疫应答的诱导。

DESCRIPTION (provided by applicant): There is as yet no effective vaccine to HIV despite concerted efforts by numerous groups worldwide to produce one. The target for vaccines is the envelope spike protein (gp120/gp41), which mediates binding to receptors on the surface of CD4 T cells. The problem from a vaccine perspective is that the spike protein is heavily glycosylated, with up to 25 or more N-linked glycans, creating a 'glycan shield' that prevent an immune response to the underlying protein. Yet, many HIV infected individuals develop broadly neutralizing antibodies (bnAbs) that target the dense array of glycans. Analysis these glycan- dependent bnAbs show that they bind to different regions on the spike protein, and that they recognize different types of glycans. In particular, some antibodies exhibit high specificity for unprocessed 'high mannose' type glycans, while others exhibit specificity for more highly processed 'complex type' glycans. A major gap in current knowledge is what types of glycans are present at each glycosylation site on gp120/gp41 on the intact virus. This is critical information for understanding the optimal epitopes of glycan-dependent bnAbs. In this project we seek to better define the epitopes of glycan-dependent bnAbs, and use the information to develop immunogens that elicit a neutralizing immune response that targets the glycan shield. We will use a novel glyco-proteomics approach to analyze and determine type of glycan (high mannose or complex) for each glycosylation site on gp120/gp41 from HIV viruses produced in laboratory cell lines and peripheral blood mononuclear cells. We will use this information to produce synthetic scaffolds that carry defined glycans for characterization of the optimal epitopes of bnAbs, and to generate recombinant gp120 immunogens that approximate the glycosylation of gp120 on intact virus. Both the synthetic scaffolds and glycosylation optimized recombinant gp120 trimers will be tested for induction of neutralizing immune responses mediated by glycan-dependent gp120 antibodies.