Characterization of HIV-1 IgA bNAbs and ADCP function

项目摘要 HIV-1主要通过粘膜接触传播。IgA在粘膜分泌物中占主导地位，长期以来一直是一类 在入口处需要抗体来阻止感染。然而，由于缺乏伊加反应， 与IgG相比，HIV-1以前的抗体分离工作和抗体库分析集中在 IgG+ B细胞和伊加+ B细胞缺失。通过一种新的基于水泡性口炎病毒（VSV）的平台，我们 能够在表面展示膜包埋的HIV-1包膜（Env）三聚体，用它来探测Env特异性 记忆B细胞，并从感染个体中分离HIV-1广泛中和抗体（bNAb）。在此 在此过程中，我们将伊加转录物纳入抗体库分析，并鉴定了两种HIV-1 bNAb谱系 该类别转换为IgG和伊加，因此首次鉴定了在该过程中产生的伊加bNAb HIV-1自然感染此外，我们还分离了两个HIV-1 Env导向的伊加单克隆抗体， 显示出部分病毒中和能力的单克隆抗体（mAb）;这些IgA还介导了有效的抗体依赖性免疫应答。 细胞吞噬作用（ADCP）的功能是清除HIV-1感染的细胞。在这些科学前提的支持下， 在本申请中，我们提出鉴定来自进化枝B的另外的HIV-1伊加bNAb和ADCP伊加mAb， 非进化枝B感染的个体，包括那些纵向跟踪的个体（目标1），然后表征伊加 靶向HIV-1 Env上的表位（目的2），并测试代表性伊加bNAb和ADCP伊加的保护效力 恒河猴SHIV粘膜攻击模型（目的3）。我们的目标是测试假设1）显着 伊加bNAb和ADCP反应在HIV-1感染过程中引起; 2）伊加bNAb和ADCP IgA可以靶向 HIV-1 Env上新的脆弱位点; 3）伊加bNAb与其IgG bNAb对应物相当或更好 在保护免受SHIV粘膜攻击，ADCP伊加也可以保护猕猴免受SHIV粘膜攻击 挑战.如果成功，该项目将揭示和验证伊加的潜在抗病毒功能，以对抗 HIV-1

PROJECT SUMMARY HIV-1 spreads mainly through mucosal exposures. Dominant in mucosal secretions, IgA has long been the class of antibodies desired at the portal of entrance to block infection. However, due to a paucity of IgA responses to HIV-1, as compared to IgG, previous antibody isolation efforts and antibody repertoire analyses have focused on IgG+ B cells and missed IgA+ B cells. With a novel vesicular stomatitis virus (VSV)-based platform, we were able to display the membrane-embedded HIV-1 envelope (Env) trimer on the surface, use it to probe Env-specific memory B cells, and isolate HIV-1 broadly neutralizing antibodies (bNAbs) from infected individuals. During this process, we included the IgA transcripts in antibody repertoire analyses and identified two HIV-1 bNAb lineages that class-switched to both IgG and IgA, thus for the first time identified IgA bNAbs produced during the course of HIV-1 natural infection. Additionally, we have isolated two HIV-1 Env-directed IgA monoclonal antibodies (mAbs) that exhibited partial virus neutralization capability; these IgAs also mediated potent antibody-dependent cellular phagocytosis (ADCP) function to eliminate HIV-1-infected cells. Supported by these scientific premises, we propose in this application to identify additional HIV-1 IgA bNAbs and ADCP IgA mAbs from clade-B and non-clade-B infected individuals, including those followed longitudinally (Aim 1), and then characterize the IgA target epitopes on HIV-1 Env (Aim 2), and test a representative IgA bNAb and ADCP IgA for protection efficacy in rhesus macaque SHIV mucosal challenge model (Aim 3). We aim to test the hypothesis that 1) significant IgA bNAbs and ADCP responses are elicited during HIV-1 infection; 2) IgA bNAbs and ADCP IgAs may target novel sites of vulnerability on HIV-1 Env; 3) an IgA bNAb is comparable to or better than its IgG bNAb counterpart at protection against SHIV mucosal challenge, and an ADCP IgA may also protect macaques from SHIV mucosal challenge. If successful, the project will unveil and validate the potential antiviral functions of IgA to fight against HIV-1.