Novel Vaccine Targeting the Sugar Coat of HIV-1

描述(申请人提供)：该提案的长期目标是开发一种有效的碳水化合物疫苗来对抗HIV-1。HIV-1包膜糖蛋白gp120是高度糖基化的，碳水化合物约占其分子质量的50%。尽管碳水化合物抗原在HIV-1表面含量丰富，但在HIV-1疫苗设计中尚未得到充分利用。最近的研究表明，HIV-1gp120具有高密度的高甘露糖型N-糖链，尽管有些位于gp120的高变区，但大多数N-糖基化位点在HIV-1分离株中是保守的。分子模拟研究表明，高甘露糖低聚糖在gp120上形成一个寡糖微区。表位图谱显示，高甘露糖低聚糖簇最有可能构成广谱中和抗体2G12的实际表位。综上所述，这些数据表明，高甘露糖低聚糖微结构域为抗HIV疫苗的设计提供了独特的、保守的抗原结构。我们假设，含有独特的高甘露糖微域结构的免疫原将诱导能够广泛中和HIV-1初级分离株的抗体。为了验证这一假设，我们将进行两个特定目标描述的实验。在具体目标1中，我们将合成新型高甘露糖型寡糖簇，模拟HIV-1上的寡糖微域抗原结构。将选择Man9GlcNAc2作为高甘露糖低聚糖部分，并以单糖为支架(模板)呈现这些低聚糖形成簇状结构。然后，高甘露糖低聚糖簇将与免疫刺激载体蛋白KLH结合，形成功能免疫原。在具体目标2中，我们将检验用合成结合疫苗免疫将提高对HIV-1初级分离株的中和抗体反应的假设。合成的结合疫苗将用于免疫小鼠。免疫反应将使用ELISA和病毒中和试验进行分析。

DESCRIPTION (provided by applicant): The long-term goal of the proposal is to develop an effective carbohydrate-based vaccine against HIV-1. The HIV-1 envelope glycoprotein gp120 is heavily glycosylated and carbohydrates constitute approximately 50% of its molecular weight. Despite their abundance on HIV-1 surface, carbohydrate antigens have not yet been adequately exploited for HIV-1 vaccine design. Recent studies revealed that HIV-1 gp120 presents a high density of high-mannose type N-glycans and most of the N-glycosylation sites are conserved among HIV-1 isolates, even though some are located at the hypervariable regions of gp120. Molecular modeling studies indicate that the high-mannose oligosaccharides are clustered to form an oligosaccharide microdomain on gp120. Epitope mapping demonstrated that a high-mannose oligosaccharide cluster most likely constitutes the actual epitopes of the broadly neutralizing antibody 2G12. Taken together, these data suggest that the high-mannose oligosaccharide microdomain provides a unique, conserved antigenic structure for anti-HIV vaccine design. We hypothesize that immunogens incorporating the unique high-mannose microdomain structure will elicit antibodies capable of broadly neutralizing HIV-1 primary isolates. To test this hypothesis, we will perform experiments described in two specific aims. In specific aim 1, we will synthesize novel high-mannose type oligosaccharide clusters that will mimic the oligosaccharide microdomain antigenic structure on HIV-1. Man9GlcNAc2 will be chosen as the high-mannose oligosaccharide moiety and monosaccharides will be used as the scaffold (template) to present these oligosaccharides to form a clustering structure. The high-mannose oligosaccharide clusters will then be conjugated to KLH, an immune-stimulating carrier protein, to fashion a functional immunogen. In specific aim 2, we will test the hypothesis that immunization with the synthetic conjugate-vaccine will raise neutralizing antibody responses against HIV-1 primary isolates. The synthetic conjugate-vaccine will be used to immunize mice. The immune responses will be analyzed using ELISAs and virus neutralization assays.