The role of non-broadly neutralizing antibodies targeting gp41 structural epitopes in long term nonprogression of HIV infection

 描述(由申请人提供)：在当今世界3500万艾滋病毒携带者中，有一小部分人从未接受过治疗，但保留了足够的CD4帮助并抵抗进展为艾滋病。到目前为止，导致这种所谓的长期无进展(LTNP)状态的免疫学限制在很大程度上仍不清楚。某些非中和抗体在HIV攻击模型系统中显示出保护和控制作用，非中和抗体依赖的细胞细胞毒性功能被认为在最近的RV144疫苗泰国试验中起到保护作用。我们以前从LTNP受试者的B细胞中分离出一些非中和抗体，这些抗体针对HIV表面包膜蛋白gp41中的两个非线性构象三聚体依赖的表位。在初步研究中，这些表位存在于复制天然表面HIV包膜三聚体的先进候选疫苗上。在初步的血清竞争研究中，靶向这些gp41非线性构象三聚体依赖的表位在LTNP受试者中更为普遍；LTNP受试者中有50%-75%的受试者具有高抗体效价。我们假设，靶向这些非线性构象三聚体依赖的表位的抗体通过对天然表面包膜结构的功能靶向来帮助维持LTNP状态。为了探索LTNP受试者中表位靶向性的比率，我们将招募更多的LTNP(每组至少45人)来比较进展中的受试者、接受治疗的受试者和HIV阴性对照样本的水平。我们已经在纽约州各地的艾滋病护理诊所建立了合作关系。为了测量这些结构靶向的抗体与一组HIV抗原的结合，包括建议的疫苗构建，我们将重组表达一组包含gp41表位的HIV抗原。该小组将包括主要的候选疫苗和突变的抗原形式，以确认结合的特异性。将使用基于酶联免疫吸附试验、天然凝胶漂移分析和表面等离子共振来确认结合和鉴定靶抗原的特异性。为了确定这些抗体在协助LTNP状态方面的功能，我们将通过这些抗体来测试抗体依赖细胞的细胞毒性。通过充分表征依赖于非线性构象三聚体的抗体及其靶标，我们将为未来的免疫原性研究提供基础，以测试这些表位是否有助于保护或控制。

 DESCRIPTION (provided by applicant): Of the 35 million living with HIV in the world today, small percentages have never received therapy but retain adequate CD4 help and resist progression to AIDS. To date, the immunological constraints leading to this so-called long-term non-progression (LTNP) state remain largely unknown. Certain non-neutralizing antibodies (Abs) have shown protection and control in HIV challenge model systems and the non-neutralizing antibody-dependent cell-cytotoxicity function is thought to play a role in protection seen in the recent RV144 vaccine `Thai Trial'.We have previously isolated a number of non-neutralizing Abs from LTNP subjects' B cells that target two non-linear conformational trimer-dependent epitopes in the HIV surface envelope protein gp41. In preliminary studies these epitopes are present on advanced vaccine candidates that replicate the native surface HIV envelope trimer. In preliminary serum competition studies, targeting of these gp41 non-linear conformational trimer dependent epitopes is more prevalent in LTNP subjects; with 50- 75% of LTNP subjects having high Ab titers. We hypothesize that Abs targeting these non-linear conformational trimer dependent epitopes assist in maintaining the LTNP state by functional targeting of native surface envelope structure. To explore rates of epitope targeting in LTNP subjects, we will recruit a larger number (45 minimum in each arm) of LTNP to compare levels to progressing subjects, maintained on therapy, and HIV negative control samples. We have established collaborations at HIV care clinics across New York State. To measure binding of these structurally targeted Abs to a panel of HIV antigens including proposed vaccine constructs, we will recombinantly express a panel of HIV antigens containing gp41 epitopes. This panel will include leading vaccine candidates and mutated forms of antigen to confirm specificity of binding. ELISA based assays, native gel shift assays and surface plasmon resonance will be used to confirm binding and characterize the specificity of targeted antigen. To identify the function of these Abs in assisting the LTNP state, we will test antibody dependent cell cytotoxicity by these Abs. By fully characterizing the non-linear conformational trimer dependent Abs and their targets, we will provide the basis for future immunogenicity studies to test if these epitopes can assist in protection or control.