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

描述（由申请方提供）：与感染后期的病毒相比，传播HIV的包膜糖蛋白糖基化程度较低。添加或转移聚糖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抗体表位。因此，在某些个体中，病毒进化可能为产生广泛中和抗体提供刺激。我们假设早期菌株特异性中和抗体靶向暴露的肽结构，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RV 144疫苗试验中引发的抗体不能介导中和是因为它们不能识别聚糖。我们将使用CAPRISA队列中HIV感染妇女和RV 144 HIV疫苗试验中特征良好的系列样本来探索这些假设。将在聚糖阵列上运行血清样本，以确定聚糖结合抗体是否优先在后来出现中和宽度的感染女性中发现，并评估RV 144样本中聚糖反应性的总体水平。识别V2区域中K169残基的V2结合抗体是RV 144中的免疫相关性的发现，使我们将注意力集中在产生靶向该相同残基并且是聚糖依赖性的广泛中和抗体的感染女性。我们将使用新的V1/V2支架，结合聚糖反应性广泛中和PG 9单克隆抗体，研究V2抗体如何发展。将对支架进行修饰，以表征抗体特异性和聚糖反应性随时间的变化，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抗V2应答的个体中是否有质的不同，以及在RV 144中引起的V2特异性是否与自然感染中引起的相似。最后，我们将评估V2结合抗体是否是广泛中和V2抗体的前体，广泛中和V2抗体在某些HIV感染者中产生，方法是使用单B细胞分选在早期和晚期时间点从选定的CAPRISA妇女中分离V2抗原特异性mAb。将评估这些mAb的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细胞培养分离了这些和其他广泛中和mAb的抗体基因，将对其进行分析，以确定哪些特征与中和宽度的获得相关。总的来说，这些数据将揭示抗V2抗体的中和宽度的途径，这可能对理解和改进RV 144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.