Effects of glycan modification on receptor binding site & immunogen of HIV-1 Env

能诱导抗多种人血吸虫分离株的中和抗体（NtAb）的免疫原的设计 免疫缺陷病毒（HIV）仍然是艾滋病疫苗研究中未达到的目标。多种因素可能 导致难以广泛产生抗HIV的NtAb。这些包括构象掩蔽 受体和辅助受体结合位点（BS）周围的保守表位以及聚糖的封闭 部分（“聚糖屏蔽”）。我们最近证明，去除C末端的N连接聚糖 HIV-1 gp 120的V2环的茎导致对CD 4 bs抗体的中和敏感性增加， 突变体Env介导CD 4非依赖性感染的能力。用这种突变的Env免疫， 交叉反应性NtAb反应中的作用。基于这些发现，我们假设：（1）变化 由特异性聚糖修饰导致的增加的稳定性或保守表位的可接近性 在受体/辅助受体B中;（2）这些保守位点的更大的可及性增强了它们的功能， 交叉反应性NtAb应答的靶点。在这个项目中，我们建议通过以下方式来验证这些假设： 检查特异性聚糖修饰、受体/辅助受体结合特性和 修饰的Env诱导交叉反应性NtAb和对抗SHIV攻击的能力， 猕猴 具体目标： 1.确定特异性N-连接聚糖修饰对Env抗原性、功能完整性 受体/辅助受体使用和免疫原性 2.为了比较来自嗜巨噬细胞R5病毒的天然和修饰的Env的免疫原性， 表现出对CD 4的不同亲和力和对CD 4 bs抗体的敏感性（来自项目1） 3.检查聚糖修饰对一组Env的影响，这些Env显示出增强的诱导 交叉反应性NtAb应答（来自项目2） 4.检测修饰的Env免疫原在猕猴攻击模型中的保护效力 这些研究的结果可能会为设计能够 引发针对不同HIV-1分离株的NtAb。 相关性（参见说明）：

Design of immunogens capable of inducing neutralizing antibodies (NtAb) against diverse isolates of human immunodeficiency virus (HIV) remains an unmet goal in AIDS vaccines research. Multiple factors may contribute to the difficulty in generating broadly NtAb against HIV. These include conformational masking of the conserved epitopes around the receptor and coreceptor binding sites (bs), as well as occlusion by glycan moieties ("glycan shield"). We recently demonstrated that removal of an N-linked glycan in the C-terminal stem of the V2 loop of HIV-1 gp120 resulted in increased neutralizing sensitivity to CD4bs antibodies and the ability of the mutant Env to mediate CD4-independent infection. Immunization with this mutant Env resulted in cross-reactive NtAb responses in macaques. Based on these findings, we hypothesize that: (1) changes resulting from specific glycan modifications lead to increased stability or accessibility of conserved epitopes in the receptor/coreceptor bs; (2) greater accessibility of these conserved sites enhances their function as targets for cross-reactive NtAb responses. In this project, we propose to test these hypotheses by examining the correlation between specific glycan modifications, receptor/coreceptor binding properties and the ability of the modified Env to induce cross-reactive NtAb and to project against SHIV challenge in macaques. Specific Aims: 1. To determine the effect of specific N-linked glycan modifications on Env antigenicity, functional integrity, receptor/coreceptor usage, and immunogenity 2. To compare the immunogenicity of native and modified Env from macrophage-tropic R5 viruses that exhibit differential affinity for CD4 and sensitivity to CD4bs antibodies (from Project 1) 3. To examine the effect of glycan modifications on a panel of Env that show enhanced ability to induce cross-reactive NtAb responses (from Project 2) 4. To examine the protective efficacy of modified Env immunogens in macaque challenge models Results from these studies are likely to provide further insight for the design of immunogens capable of eliciting NtAb against diverse isolates of HIV-1. RELEVANCE (Seeinstructions):