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

描述(由申请人提供)：与后来感染的病毒相比，传播的艾滋病毒的包膜糖蛋白糖基化程度较低。多聚糖被添加或转移以逃避特定菌株的中和抗体，在某些情况下，这些有助于形成广泛的中和抗体表位。因此，在一些个体中，病毒的进化可能会为广泛中和抗体的发展提供刺激。我们假设早期的菌株特异性中和抗体针对暴露的多肽结构，而来自同一克隆型的后来亲和力成熟的抗体识别糖化表位。第二种假设是，在RV144疫苗试验中产生的抗体无法调节中和作用，是因为它们无法识别多糖。我们将使用CAPRISA队列中HIV感染妇女和RV144 HIV疫苗试验中具有良好特征的系列样本来探索这些假设。血清样本将在葡聚糖阵列上运行，以确定是否在后来出现中和广度的受感染妇女中优先发现与葡聚糖结合的抗体，并评估RV144样本中葡聚糖反应性的总体水平。识别V2区域K169残基的V2结合抗体与RV144中的免疫相关，这一发现使我们将重点放在了感染的女性身上，她们产生了针对相同残基的广泛中和抗体，并且依赖于糖。我们将使用新型的V1/V2支架结合具有广泛中和功能的糖蛋白反应的PG9单抗来研究V2抗体的发展。支架将经过修饰，以表征抗体的特异性和随时间推移的糖蛋白反应性，并用于吸附实验，以评估V2导向的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反应的个体中是否有质的不同，以及在RV144中诱导的V2特异性是否与在自然感染中诱导的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感染者身上产生的广泛中和V2抗体的前驱，方法是在选定的CAPRISA妇女的早期和晚期时间点使用单一B细胞分选分离V2抗原特异性单抗。将评估这些单抗的糖链结合和功能活性，包括中和和抑制结合。我们的合作者最近通过B细胞培养分离了来自这些和其他广泛中和单抗的抗体基因，将对其进行分析，以确定哪些特征与获得中和广度有关。总而言之，这些数据将揭示抗V2抗体中和广度的途径，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.