Evolution of glycan-reactive broadly neutralizing anti-v2 antibodies in HIV infec

描述（由申请人提供）：与后期感染的病毒相比，传播的HIV包膜糖蛋白的糖基化程度较低。聚糖被添加或转移以逃避菌株特异性中和抗体，在某些情况下，这些有助于形成广泛中和的抗体表位。因此，在某些个体中，病毒进化可能为广泛中和抗体的产生提供刺激。我们假设，早期的菌株特异性中和抗体针对暴露的肽结构，而来自相同克隆型的后期亲和力成熟抗体识别糖基化表位。第二个假设是，在RV144疫苗试验中引发的抗体无法介导中和是因为它们不能识别聚糖。我们将使用CAPRISA队列和RV144 HIV疫苗试验中HIV感染妇女的具有良好特征的系列样本来探索这些假设。血清样本将在聚糖阵列上运行，以确定在感染妇女中是否优先发现聚糖结合抗体，这些妇女后来发展为中和广度，并评估RV144样本中聚糖反应性的总体水平。发现识别V2区K169残基的V2结合抗体在RV144中具有免疫相关性，这使我们将注意力集中在感染妇女身上，她们产生了针对相同残基的广泛中和抗体，并且是聚糖依赖性的。我们将使用新型的V1/V2支架，结合聚糖反应性广泛中和的PG9单克隆抗体来研究V2抗体的产生。随着时间的推移，支架将被修饰以表征抗体特异性和聚糖反应性，并用于吸附实验以评估v2定向血浆抗体的中和能力。我们将确定抗V2结合抗体在后来产生广泛中和性抗V2反应的个体中是否有质的不同，以及RV144中引发的V2特异性是否与自然感染中引发的V2特异性相似。最后，我们将评估V2结合抗体是否是在一些HIV感染个体中产生的广泛中和V2抗体的前体，方法是在选择的CAPRISA妇女的早期和晚期时间点使用单B细胞分选分离V2抗原特异性单抗。这些单抗将被评估为聚糖结合和功能活性，包括中和和抑制¿4¿7结合。我们的合作者最近通过B细胞培养从这些和其他广泛中和的单克隆抗体中分离出抗体基因，将对其进行分析，以确定哪些特征与获得中和广度相关。总的来说，这些数据将揭示抗v2抗体中和宽度的途径，这可能对理解和改进RV144结果具有重要意义。

DESCRIPTION (provided by applicant): The envelope glycoprotein of transmitted HIV is less glycosylated compared to viruses from later in infection. Glycans are added or shifted to escape strain-specific neutralizing antibodies, and in some cases these contribute to the formation of broadly neutralizing antibody epitopes. Thus, in some individuals, viral evolution may provide the stimulus for the development of broadly neutralizing antibodies. We hypothesize that early strain-specific neutralizing antibodies target exposed peptidic structures while later affinity matured antibodies from the same clonotype recognize the glycosylated epitope. A secondary hypothesis is that the inability of antibodies elicited in the RV144 vaccine trial to mediate neutralization is because they fail to recognize glycans. We will explore these hypotheses using well-characterized serial samples from HIV-infected women in the CAPRISA cohort and from the RV144 HIV vaccine trial. Serum samples will be run on glycan arrays to determine whether glycan-binding antibodies are preferentially found in infected women who later develop neutralization breadth and to assess overall levels of glycan reactivity in RV144 samples. The finding that V2 binding antibodies that recognize the K169 residue in the V2 region are an immune correlate in RV144, has led us to focus on infected women who develop broadly neutralizing antibodies that target this same residue and are glycan-dependent. We will use novel V1/V2 scaffolds that bind the glycan-reactive broadly neutralizing PG9 monoclonal antibody to study how V2 antibodies develop. Scaffolds will be modified in order to characterize antibody specificities and glycan-reactivity over time, and used in adsorption experiments to assess the neutralizing capacity of V2-directed plasma antibodies. We will define whether anti-V2 binding antibodies are qualitatively different in individuals who later develop broadly neutralizing anti-V2 responses, and whether the V2 specificities elicited in RV144 are similar to those elicited in natural infection. Finally, we will assess whether V2 binding antibodies are the precursors of broadly neutralizing V2 antibodies that develop in some HIV infected individuals by isolating V2 antigen-specific mAbs using single B cell sorting at early and late time points from selected CAPRISA women. These mAbs will be assessed for glycan-binding and functional activity including neutralization and inhibition of ¿4¿7 binding. Antibody genes from these and other broadly neutralizing mAbs, recently isolated through B cell culture by our collaborators, will be analyzed to determine which features associate with the acquisition of neutralization breadth. Collectively, these data will reveal the pathway to neutralization breadth for anti-V2 antibodies, which may have important implications for understanding and improving on the RV144 results.