Alpha-galactosycleramide as a mucosal adjuvant for HIV antigens

说明(申请人提供)：预防由人类免疫缺陷病毒(HIV)感染引起的获得性免疫缺陷综合征(AIDS)等性传播疾病的疫苗接种，应集中于诱导强烈的抗原特异性体液和细胞免疫反应，作为病毒进入的粘膜屏障。然而，将疫苗，特别是基于蛋白质的疫苗，输送到粘膜表面通常效率低下，需要使用合适的佐剂，这些佐剂可以直接增强效应器T细胞和抗原提呈细胞(APC)，如树突状细胞(DC)，和/或动员先天免疫反应。合成糖脂α-氨基半乳糖神经酰胺(AGalCer)是天然杀伤T(NKT)细胞的有效激活剂，是一种主要的天然免疫介导性细胞类型，在几个动物模型研究中被证明是安全和有效的，用于增强对肿瘤疫苗的特异性免疫反应。我们获得的初步数据显示，只有在联合注射aGalCer的情况下，小鼠鼻腔和口服后才能诱导对HIV和非HIV多肽抗原的全身和粘膜细胞免疫反应。基于这些结果，我们推测，以aGalCer为佐剂的HIV抗原粘膜递送将是一种安全有效的方法，可以诱导强烈的粘膜和系统免疫。此外，我们假设粘膜间隔的DC可以被GalCer介导的NKT细胞反应激活，从而使DC能够将HIV抗原肽递送给CD4+和CD8+T细胞。我们建议利用aGalCer的佐剂潜力，使用HIV-1包膜蛋白作为测试抗原，通过粘膜途径特异性地传递，以启动有效的粘膜和系统免疫反应。我们建议的研究还将分析aGalCer佐剂活性的潜在机制。为达致这些目标，我们建议： 评估aGalCer的粘膜佐剂活性，用于通过鼻腔和口腔途径启动对HIV-1的体液和细胞免疫反应，作为蛋白质或从腺病毒载体表达。 确定当aGalCer用于通过鼻腔和口服途径将抗原输送到小鼠体内时，NKT细胞的动力学与粘膜和全身隔室中DC的激活和抗原特异性T细胞的预置之间的潜在联系。 成功的结果(即使用aGalCer作为粘膜佐剂有效地诱导粘膜和系统抗原特异性免疫反应)将使我们能够在未来的提案中扩大免疫原性研究，在由印度源恒河猴组成的非人类灵长类动物模型中测试HIV/SIV疫苗候选，然后用致病的SIV/SIV毒株进行针对黏膜攻击的有效性测试。公共卫生相关性：成功的结果(即有效地诱导粘膜和系统抗原特异性免疫反应)将使我们能够在未来的提案中扩大免疫原性研究，在由印度源恒河猴组成的非人类灵长类动物模型中测试HIV/SIV候选疫苗，然后进行针对致病SIV/SIV毒株的黏膜挑战的有效性测试。

DESCRIPTION (provided by applicant): Vaccination for protection against sexually transmitted diseases such as acquired immunodeficiency syndrome (AIDS) caused by human immunodeficiency virus (HIV) infection should concentrate on inducing strong antigen-specific humoral and cellular immune responses as a mucosal barrier for viral entry. However, delivery of vaccines, specifically those based on proteins, to the mucosal surfaces is generally inefficient and requires the use of suitable adjuvants that could directly potentiate the effector T cells and the antigen-presenting cells (APC), such as the dendritic cells (DC), and/or mobilize the innate immune responses. The synthetic glycolipid alpha-glactosylceramide (aGalCer), a potent activator of natural killer T (NKT) cells, a major innate immune mediator cell type, has been shown to be safe and effective when administered by the parenteral routes for enhancing specific immune responses to tumor vaccines in several animal model studies. We obtained pilot data showing induction of systemic and mucosal cellular immune responses to HIV as well as non-HIV peptide antigens after intranasal and oral delivery in mice only when aGalCer was co-administered. Based on these results we hypothesize that mucosal delivery of HIV antigens using aGalCer as adjuvant will be a safe and effective approach for inducing strong mucosal and systemic immunity. Furthermore, we hypothesize that DC at mucosal compartments can be activated by aGalCer-mediated NKT cell responses to enable the DC to present HIV antigenic peptides to CD4+ and CD8+ T cells. We propose to harness the adjuvant potential of aGalCer employing the HIV-1 envelope protein, as a test antigen, specifically delivered by the mucosal routes to prime efficient mucosal and systemic immune responses. Our proposed studies will also analyze the underlying mechanisms for the adjuvant activity of aGalCer. To achieve these goals we propose to: Evaluate mucosal adjuvant activity of aGalCer for priming humoral and cellular immune responses to HIV-1 delivered, as protein or expressed from adenoviral vector, by the intranasal and oral routes. Determine potential associations between the kinetics of NKT cell and DC activation and priming of antigen-specific T cells in the mucosal and systemic compartments when aGalCer is used for delivery of antigens by the intranasal and oral routes to mice. Successful outcome (i.e. potent induction of mucosal and systemic antigen-specific immune responses using aGalCer as mucosal adjuvant) will enable us to extend the immunogenicity studies in future proposals for testing HIV/SIV vaccine candidates in the nonhuman primate model comprised of Indian-origin rhesus macaques followed by efficacy testing against mucosal challenge with pathogenic SIV/SHIV strains. PUBLIC HEALTH RELEVANCE: Successful outcome (i.e. potent induction of mucosal and systemic antigen-specific immune responses) will enable us to extend the immunogenicity studies in future proposals for testing HIV/SIV vaccine candidates in the nonhuman primate model comprised of Indian-origin rhesus macaques followed by efficacy testing against mucosal challenge with pathogenic SIV/SHIV strains.