Discovery of Novel Epitopes for Antibody Dependent Cell-mediated Cytotoxicity Against HIV-1 Infected Cells

项目摘要/摘要 艾滋病毒的研究工作主要集中在开发能够产生高度保护性抗体的疫苗上。 回应。有来自人类和非人类疫苗研究的证据表明，中和和非人类疫苗 中和抗体活性有助于防止感染。重要的是，唯一的三期疫苗 在人类志愿者身上显示保护信号的疗效试验表明，抗体依赖细胞- 介导的细胞毒性(ADCC)与获得的减少有关，迫使我们对此有更多的了解 Fc介导的抗病毒作用。我们之前发现了一组独一无二的300多个单抗 来自赞比亚和卢旺达的6名最近感染HIV-1的人的抗体，发现这些抗体的子集 抗体介导针对包被来自自体的包膜gp120蛋白的靶细胞的ADCC， 已传输/方正(T/F)变体。这种活性与CDRH3区较短的抗体有关 对T/F包膜伪病毒的中和活性低于缺乏ADCC活性的抗体。 建模和竞争研究表明，一些ADCC介导的抗体识别新的 表位。在这里，我们将测试这些针对ADCC的单抗，以对抗感染正品的靶细胞 通过分子克隆产生T/F变异体，并与ADCC与包被的靶细胞进行比较 T/F gp120蛋白和T/F Env的中和，后者是抗体结合的标志 功能性的、与病毒粒子相关的包膜尖峰。大量使用自体T/F包膜抗体 组合，其中包络表示确切的表位或非常接近于 抗体的选择，以及两种广泛使用的ADCC检测，我们的研究有可能揭示 ADCC以前不为人知的机制特征，并确定可以进一步 开发和探索疫苗。

Project Summary/Abstract HIV research efforts are strongly focused on developing vaccines that can elicit highly protective antibody responses. There is evidence from human and nonhuman vaccine studies that both neutralizing and non- neutralizing antibody activities contribute to protection against acquisition. Importantly, the only phase III vaccine efficacy trial to show a signal of protection in human volunteers demonstrated that antibody dependent cell- mediated cytotoxicity (ADCC) was associated with reduced acquisition, compelling us to know more about this Fc-mediated antiviral function. We previously recovered a unique collection of more than 300 monoclonal antibodies from 6 recently HIV-1 infected individuals from Zambia and Rwanda and found that a subset of these antibodies mediated ADCC against target cells coated with the envelope gp120 protein from the autologous, transmitted/founder (T/F) variant. This activity was associated with antibodies that had shorter CDRH3 regions and lower neutralization activity against the T/F envelope pseudovirus than antibodies lacking ADCC activity. Modeling and competition studies suggested that some of the ADCC-mediating antibodies recognize novel epitopes. Here, we will test these monoclonal antibodies for ADCC against target cells infected with the authentic T/F variant created by molecular cloning, and compare the results with ADCC against target cells coated with the T/F gp120 protein and neutralization of the T/F Env, the latter being the hallmark of antibody binding to the functional, virion-associated envelope spike. By using a large number of autologous T/F envelope-antibody combinations, where the envelope presents the exact epitope or a very close approximation to that which the antibody was selected against, and two widely used ADCC assays, our studies have the potential to reveal previously unappreciated mechanistic features of ADCC and identify novel epitopes that can be further developed and explored for vaccines.