CD1d/NKT-binding glycolipids in enhancing the immunogenicity of a malaria vaccine

描述（由申请人提供）：根除全球病原体，包括疟疾，取决于有效疫苗的开发。实现成功疫苗的关键策略之一是鉴定和开发基于新机制的佐剂。?-半乳糖神经酰胺（？GalCer）是一种已经被广泛研究的糖脂，已知其通过结合CD 1d分子并刺激免疫应答的重要亚群不变NKT（iNKT）细胞而显示出显著的生物活性，包括佐剂效应。最近我们发现了一本小说GalCer类似物，7 DW 8 -5，其在肌肉内（i. m.）与候选疟疾疫苗共同施用。相比之下，？GalCer，其亲本糖脂，我们发现7 DW 8 -5的佐剂作用明显优于上级。7 DW 8 -5不仅对iNKT细胞和树突状细胞（DCs）具有更强的刺激活性，而且与小鼠和人CD 1d分子的结合亲和力也比？GalCer。非常令人惊讶的是，我们发现，当通过肌肉注射给药时，注射，只有？GalCer，但不是7 DW 8 -5，诱导细胞因子，包括IFN-？和IL-12，而两种糖脂在静脉内给药后诱导相似水平的全身细胞因子产生。我们假设7 DW 8 -5在肌内局部保留。注射部位和附近的引流淋巴结，这是由于其对CD 1d分子的更高结合亲和力和/或通过7 DW 8 -5上调活化的DC上的CD 1d表达水平。因此，在目的1中，我们将首先确定7 DW 8 -5是否确实局部保留，如果是，如何防止7 DW 8 -5扩散并诱导全身性细胞因子产生。我们还怀疑其局部保留与7 DW 8 -5所发挥的上级佐剂作用直接相关，并假设7 DW 8 -5诱导的DC活化增加导致疫苗引发的适应性免疫应答的更强发作。我们将在目标2中检验这一假设。最后，目前还不清楚7 DW 8 -5是否真的可以增强体液和CD 4 + T细胞应答，以及这些应答是否有助于预防疟疾。因此，使用缺乏CD 8 + T细胞和/或抗体的小鼠，我们将在目标3中确定这些问题。鉴于我们最近的研究表明，7 DW 8 -5对非人灵长类动物中基于腺病毒的疟疾疫苗的细胞免疫原性提供了显著的佐剂作用，并且由于7 DW 8 -5在2012年正进入1期临床试验，因此所提出的研究对于7 DW 8 -5的未来临床应用应该是必要的，不仅作为各种疫苗的佐剂，也可作为直接治疗剂。 公共卫生相关性：疟疾继续对全球社会构成严重威胁，特别是对前往或生活在世界热带和亚热带地区的成人和儿童构成严重威胁。这项提案的目的是研究和了解如何通过采用糖脂作为免疫增强化合物或“佐剂”来增强疟疾疫苗的效力。“开发一种合适的疟疾疫苗/糖脂佐剂组合将有可能降低疟疾的发病率，减少这种病原体引起的发病率和死亡率。

DESCRIPTION (provided by applicant): The eradication of global pathogens, including malaria, hinges upon the development of effective vaccines. One of the key strategies to realize successful vaccines is to identify and develop a new mechanism-based adjuvant. ?-galactocylceramide (?-GalCer), a glycolipid that has been extensively investigated, is known to display a significant biological activity, including an adjuvant effect, by binding CD1d molecules and stimulating invariant NKT (iNKT) cells, an important sub-population of the immune response. Recently, we identified a novel ?-GalCer analog, 7DW8-5, which can strongly enhance the level of malaria-specific protective immune response upon its intra-muscular (i.m.) co-administration with a candidate malaria vaccine. When compared to ?-GalCer, its parental glycolipid, we found the adjuvant effect of 7DW8-5 to be clearly superior. 7DW8-5 exhibited not only a stronger stimulatory activity towards iNKT cells and dendritic cells (DCs), but also a higher binding affinity to both mouse and human CD1d molecules than ?-GalCer. Very surprisingly, we discovered that when administered by i.m. injection, only ?-GalCer, but not 7DW8-5, induced a systemic production of cytokines including IFN-? and IL-12, whereas both glycolipids induced a similar level of systemic cytokine production upon their intravenous administration. We hypothesize that 7DW8-5 is retained locally at the i.m. injection site and nearby draining lymph nodes due its higher binding affinity to CD1d molecules and/or the up- regulation of CD1d expression level on activated DCs by 7DW8-5. In Aim 1, therefore, we will first determine whether 7DW8-5 is indeed retained locally and if so, how 7DW8-5 is prevented from spreading out and inducing systemic cytokine production. We also suspect that its local retention is directly related to the superior adjuvant effect exerted by 7DW8-5 and hypothesize that an increased activation of DCs induced by 7DW8-5 results in a stronger onset of the adaptive immune response elicited by vaccines. We will test this hypothesis in Aim 2. Finally, it is still unclear whether 7DW8-5 could indeed enhance humoral and CD4+ T cell responses and whether these responses could contribute to the protection against malaria. Therefore, using mice lacking CD8+ T cells and/or antibodies, we will determine these issues in Aim 3. In view of our recent studies showing that 7DW8-5 provides a significant adjuvant effect on the cellular immunogenicity of an adenovirus-based malaria vaccine in non-human primates, and because 7DW8-5 is advancing into a Phase 1 clinical trial in 2012, the proposed studies should be imperative for the future clinical applications of 7DW8-5 not only as an adjuvant for various vaccines, but also as a direct therapeutic agent. PUBLIC HEALTH RELEVANCE: Malaria continues to pose a grave threat to the global community and in particular to adults and children traveling to or living in tropical and subtropicl regions of the world. The purpose of this proposal is to study and understand how the efficacy of malaria vaccines gets enhanced by employing glycolipids as immuno- enhancing compounds or "adjuvants." The development of a suitable malaria vaccine/glycolipid adjuvant combination would have the potential to decrease the incidence of malaria and diminish the morbidity and mortality attributable to this pathogen.