HIV-1 vaccine-elicited antibodies target envelope glycans

项目摘要 HIV-1包膜糖蛋白的抗体识别受到密集包装的宿主聚糖的阻碍 包裹在Env的表面。与Env聚糖相互作用的抗体具有发展广泛的HIV-1的潜力。 1反应性和中和。然而，宿主聚糖的免疫原性差，这对免疫原性产生了挑战。 引发聚糖反应性中和抗体。在我们的第一个任期内，我们定义了一种新的 中和HIV-1抗体，结合保护HIV-1包膜的聚糖。这些抗体 分离自多次接种疫苗的猕猴和猿猴-人免疫缺陷病毒感染的猕猴。 与已知的聚糖依赖性HIV-1抗体不同，这些抗体表现出形成I形免疫球蛋白的能力。 和Y形IgG分子，并通过由重链可变区形成的深腔与聚糖结合。 地区我们将这种类型的抗体称为Fab二聚聚糖（FDG）抗体，因为聚糖的二聚化 Fab产生I形构象。疫苗诱导的FDG抗体广泛中和HIV-1， 病毒糖基化限于Man 9 GlcNAc 2-这些被称为I型FDG抗体。II型FDG 抗体类似于I型，除了它们不需要Man 9 GlcNAc 2富集来中和抗体。 启动抗体谱系的自体病毒。此外，来自感染者的III型FDG抗体 猕猴比I型疫苗诱导的FDG抗体结合更多的糖基化位点，并表现出广泛的 HIV-1中和活性与HIV-1包膜上存在的聚糖类型无关。科学前提 FDG抗体中和HIV-1的宽度依赖于抗体 多个Env糖基化位点的识别，以及每个Env上不同聚糖的抗体识别 糖基化位点本研究的目的是指导抗体亲和力成熟和从I型抗体中选择。 FDG抗体与III型FDG抗体。我们已经设计了结构和抗原模拟物， 这些抗体靶向Env的糖基化区域，并将该糖肽的24个拷贝排列在 蛋白质纳米颗粒。我们建议从接种疫苗的猕猴中分离FDG抗体， 他们的抗体正在发展成为III型广泛中和FDG抗体（目标1）;确定 I型和III型FDG抗体之间的共同遗传或生化特征，这些特征有助于 中和宽度的发展（目的2）;并在猕猴中用Env 最小免疫原纳米颗粒（Aim 3）。这项工作是重要的，因为它将确定一个路径， 引发HIV-1广泛中和抗体，并将混杂聚糖识别定义为 FDG抗体发生中和宽度的机制。这种方法将产生巨大的影响 因为它将展示一种诱导HIV-1 bnAb的替代疫苗方法， 不需要靶向和引导广泛中和抗体的稀有前体。

PROJECT SUMMARY Antibody recognition of the HIV-1 envelope (Env) glycoprotein is hindered by the densely-packed host glycans that coat the surface of Env. Antibodies that interact with Env glycans have the potential to develop broad HIV- 1 reactivity and neutralization. However, host glycans are poorly immunogenic, presenting a challenge for eliciting glycan-reactive neutralizing antibodies. In the first term of our grant, we defined a new type of neutralizing HIV-1 antibody that bound the glycans that shield the HIV-1 envelope. These antibodies were isolated from multiple vaccinated macaques and simian-human immunodeficiency virus-infected macaques. Distinct from known glycan-dependent HIV-1 antibodies, these antibodies exhibited the ability to form I-shaped and Y-shaped IgG molecules, and bound to glycans via a deep cavity formed by the heavy chain variable region. We termed this type of antibody Fab-dimerized glycan (FDG) antibodies, since the dimerization of the Fabs generated the I-shaped conformation. Vaccine-induced FDG antibodies broadly neutralize HIV-1 when the virus glycosylation is restricted to Man9GlcNAc2–these are termed Type I FDG antibodies. Type II FDG antibodies are similar to Type I, except they do not require Man9GlcNAc2 enrichment for neutralization of the autologous virus that initiated the antibody lineage. Additionally, Type III FDG antibodies from infected macaques bind to more glycosylation sites than Type I vaccine-induced FDG antibodies, and exhibit broad HIV-1 neutralizing activity irrespective of the type of glycan present on HIV-1 envelope. The scientific premise of this work is that the development of FDG antibody HIV-1 neutralization breadth is dependent upon antibody recognition of multiple Env glycosylation sites, and antibody recognition of diverse glycans at each Env glycosylation site. The goal of this study will be to guide antibody affinity maturation and selection from Type I FDG antibodies to Type III FDG antibodies. We have designed structural and antigenic mimics of the glycosylated region of Env targeted by these antibodies, and arrayed 24 copies of this glycopeptide on a protein nanoparticle. We propose to isolate FDG antibodies from vaccinated macaques whose serum suggests their antibodies are developing into Type III broadly neutralizing FDG antibodies (Aim 1); determine the common genetic or biochemical features between Type I and Type III FDG antibodies that contribute to the development of neutralization breadth (Aim 2); and elicit Type III FDG antibodies in macaques with Env minimal immunogen nanoparticles (Aim 3). This work is significant because it will define a path for reproducibly eliciting HIV-1 broadly neutralizing antibodies, and it will define promiscuous glycan recognition as the mechanism by which neutralization breadth occurs for FDG antibodies. This approach would have great impact on the field as it will demonstrate an alternative vaccine approach for the induction of HIV-1 bnAbs that does not require targeting and shepherding rare precursors of broadly neutralizing antibodies.