Mimotope Conversion of HIV-1 Carbohydrate Antigens

碳水化合物抗原是引发针对许多病原体的保护性免疫应答的基础，但这种方法在HIV研究中尚未得到充分评估。 抗碳水化合物抗体可促进抑制感染细胞与粘膜上树突状细胞的结合，以阻止早期感染。 我们已经开发了一个与HIV相关的碳水化合物表位相互转化为基于肽的疫苗策略的项目，以增强碳水化合物交叉反应的全身和粘膜反应。 在具体目标1中，我们检验了由HIV-1相关碳水化合物抗原的肽模拟表位诱导的免疫与由碳水化合物抗原本身诱导的免疫在定性和定量上不同的假设。 感兴趣的是根据i.抗体诱导的动力学; ii.碳水化合物/gp 120反应性同种型谱;和iii.碳水化合物/gp 120反应性抗体亲和力。评估血清与暴露于天然形式的gp 120和gp 160上的表位的结合，以及单体gp 120和细胞表面表达的寡聚gp 120/gp 41的异源菌株。在具体目标2中，我们探索了提高碳水化合物反应性滴度和扩大HIV免疫反应性广度的方法。 在用模拟物或碳水化合物制剂初免并用寡聚gp 160制剂加强后评价全身和粘膜反应。 对血清和粘膜灌洗液进行i.实验室和原代分离株的中和作用ii.树突状细胞粘附和感染的抑制iii.还评价了如目的1中的血清抗体与gp 120表位结合的评价。 在具体目标3中，使用涉及分子建模和噬菌体展示文库的系统方法来分析和利用拓扑相似性以进一步定义HIV-1相关碳水化合物抗原的原型肽模拟位模板。 在这个目标中，HIV-1相关的甘露糖和乳糖系列碳水化合物结构之间的拓扑关系与肽模拟位的结合特性相关，肽模拟位与选择的凝集素和高效的碳水化合物反应性HIV-1中和抗体2G 12反应。 我们进一步通过1.）合成和生物淘选代表反映碳水化合物和肽结构的二级结构元件的限定肽阵列文库;以及2.）通过Biacore和计算机建模研究评价配体结合的亲和力。

Carbohydrate antigens have been the basis for eliciting protective immune responses against many pathogens, yet this approach has not been adequately assessed in HIV research. Anti- carbohydrate antibodies may facilitate the inhibition of infected cell binding to dendritic cells on mucosa to thwart early infection. We have developed a program concerned with the inter- conversion of carbohydrate epitopes associated with HIV into a peptide based vaccine strategy to augment carbohydrate cross- reactive systemic and mucosal responses. In specific aim 1, we test the hypothesis that immunity induced by peptide mimeotopes of HIV-1 associated carbohydrate antigens differs qualitatively and quantitatively from the immunity induced by the carbohydrate antigen itself. Of interest is the evaluation of polyclonal responses in terms of i. kinetics of antibody induction; ii. Carbohydrate/gp120 reactive isotype profiles; and iii. Carbohydrate/gp120 reactive antibody affinity/avidity. Evaluation of serum binding to epitopes exposed on native forms of gp120 and gp160, and heterologous strains of monomeric gp120 and cell surface-expressed oligomeric gp120/gp41 are evaluated. In specific aim 2, we explore ways to enhance carbohydrate reactive titers and expand on the breadth of HIV immunoreactivity. Systemic and mucosal responses are evaluated following priming with mimetic or carbohydrate formulations and boosting with oligomeric-gp160 formulates. Serum and mucosal lavages are tested for i. Neutralization of Lab and primary isolates ii. Inhibition of Dendritic cell adherence and infection iii. Evaluation of serum antibody binding to gp120 epitopes as in aim 1 are also evaluated. In specific aim 3, systematic approaches involving molecular modeling and phage display libraries are used to analyze and exploit topological similarities to further define prototypic peptide mimeotope templates of HIV-1 associated carbohydrate antigens. In this aim, topological relationships between HIV-1 associated mannosyl and lactoseries carbohydrate structures are correlated with binding properties of peptide mimeotopes reactive with selected lectins and a highly effective carbohydrate reactive HIV-1 neutralizing antibody 2G12. We further define variants of peptides that display high affinity binding to these receptors by 1.) Synthesizing and biopanning defined peptide array libraries representative of secondary structure elements reflective of carbohydrate and peptide structures; and 2.)Evaluation of the affinity of ligand binding by Biacore and computer modeling studies.