HIV-1 vaccine-elicited antibodies target envelope glycans

项目总结 HIV-1包膜糖蛋白(Env)的抗体识别被致密的宿主多糖所阻碍 它覆盖着环境的表面。与环境多糖相互作用的抗体有可能发展为广泛的艾滋病毒- 1反应性和中和性。然而，宿主多糖的免疫原性很差，对 引发糖蛋白反应性中和抗体。在我们的第一期拨款中，我们定义了一种新型的 中和HIV-1抗体，该抗体结合保护HIV-1包膜的多糖。这些抗体是 分离自多只接种疫苗的猕猴和感染人类免疫缺陷病毒的猕猴。 与已知的依赖糖的HIV-1抗体不同，这些抗体显示出形成I型的能力 和Y-型免疫球蛋白分子，并通过重链变量形成的深腔与多糖结合 区域。我们将这种类型的抗体称为Fab-二聚糖(FDG)抗体，因为 FABS产生了I型构象。疫苗诱导的FDG抗体在以下情况下广泛中和HIV-1 病毒的糖基化仅限于Man9GlcNAc2-这些被称为I型FDG抗体。II型FDG 抗体类似于I型，不同的是它们不需要Man9GlcNAc2浓缩来中和 启动抗体谱系的自体病毒。此外，受感染的III型FDG抗体 与I型疫苗诱导的FDG抗体相比，猕猴结合更多的糖基化位点，并表现出广泛的 HIV-1的中和活性与HIV-1包膜上的多糖类型无关。科学的前提是 这项工作的重点是fdg抗体HIV-1的中和广度依赖于抗体 多个环境糖基化位点的识别和每个环境中不同糖链的抗体识别 糖基化位点。本研究的目的是指导抗体亲和力的成熟和I型抗体的筛选 抗III型FDG抗体。我们已经设计了结构和抗原性的模拟物 这些抗体靶向的Env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，这些猕猴的血清表明 他们的抗体正在发展为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 发展中和广度(目标2)；并在有环境的猕猴中激发III型FDG抗体 最小免疫原纳米粒(目标3)。这项工作意义重大，因为它将定义一条可重现的路径 引发广泛的HIV-1中和抗体，它将定义混杂的多糖识别为 FDG抗体中和广度发生的机制。这种方法会产生很大的影响 在现场，因为它将展示一种诱导HIV-1bNAbs的替代疫苗方法 不需要靶向和引导稀有的广谱中和抗体前体。

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.