Proteome-wide cellular immunity approach to P. falciparum antigen identification

描述（由申请人提供）：该项目的长期目标是通过挖掘恶性疟原虫基因组序列，确定并优先考虑在多重遗传限制的情况下暴露于恶性疟原虫的个体识别的新型恶性疟原虫抗原和表位。疟疾疫苗的可行性得到实验数据的支持，这些数据表明，接触完整的疟原虫可诱导保护性免疫。这种保护的抗原靶点尚未确定。恶性疟原虫大约表达5300种蛋白质，每一种蛋白质都是保护性免疫反应的潜在目标。虽然恶性疟原虫的基因组、蛋白质组和转录组现在已经被阐明，但如何将这些信息用于疫苗开发还不清楚。目前的应用提供了一个解决方案，通过应用集成了生物信息学预测、HLA超型考虑、高通量MHC肽结合测定和细胞测定的综合方法。具体目的是：(1)从恶性疟原虫生命周期红细胞前阶段表达的大约2500个基因的完整集合中鉴定出那些与暴露于恶性疟原虫的个体在多重遗传限制背景下识别的免疫优势抗原相对应的蛋白质；(2)对于100种最具免疫优势的抗原子集，鉴定作为恶性疟原虫诱导免疫靶点的CD8+和CD4+ T表位及其相关的HLA I类和II类限制性元件；(3)对50种抗原，鉴定5个表位/抗原的序列保守程度或不同疟原虫菌株之间的免疫交叉反应性；(4)对10种抗原，评价其在小鼠体内抵御疟原虫孢子虫攻击的能力。预计拟议的研究将导致鉴定新的恶性疟原虫抗原，这些抗原将代表对所有种族都有效的疫苗的良好候选者。此外，数据将证明保护性免疫反应是仅针对少数免疫优势抗原，还是广泛分布于大量抗原，因此将提供有关候选疟疾疫苗的潜在多价性的宝贵信息。预计拟议的研究将对疟疾疫苗的开发产生重要成果。它将确定新的恶性疟原虫抗原，这些抗原应该是一种亚单位疟疾疫苗的良好候选者，这种疫苗将对所有人群有效，无论种族。此外，数据将证明保护性免疫反应是仅针对少数免疫优势抗原，还是广泛分布于大量抗原，因此将提供有关候选疟疾疫苗的潜在多价性的宝贵信息。

DESCRIPTION (provided by applicant): The long-term objective of this project is to identify and prioritize for malaria vaccine development novel P. falciparum antigens and epitopes that are recognized by individuals exposed to P. falciparum in the context of multiple genetic restrictions, by mining the P. falciparum genomic sequence. The feasibility of a malaria vaccine is supported by experimental data demonstrating that protective immunity can be induced by exposure to intact Plasmodium parasites. The antigenic targets of this protection have not been identified. P. falciparum expresses an estimated 5,300 proteins, each of which is a potential target of protective immune responses. Although the P. falciparum genome, proteome, and transcriptome have now been elucidated, it has not been obvious how to use this information for vaccine development. The current application offers a solution to this problem, by applying an integrated approach that incorporates bioinformatic predictions, HLA supertype considerations, high-throughput MHC peptide binding assays, and cellular assays. The specific aims are to: (1) identify, from the complete set of approximately 2500 genes expressed in the pre-erythrocytic stage of the P. falciparum parasite life cycle, those proteins that correspond to immunodominant antigens recognized in the context of multiple genetic restrictions by individuals exposed to P. falciparum; (2) for a subset of the100 most immunodominant antigens, identify the CD8+ and CD4+ T epitopes that are the targets of P. falciparum parasite-induced immunity, and their associated HLA Class I and II restriction elements; (3) for 50 antigens, characterize five epitopes/antigen for extent of sequence conservation or immunological cross-reactivity between different Plasmodium strains; and (4) for 10 antigens, evaluate the capacity to protect against Plasmodium sporozoite challenge in mice. It is expected that the proposed research will result in the identification of novel P. falciparum antigens that will represent good candidates for a vaccine that would be effective in all ethnicities. Additionally, data will demonstrate whether protective immune responses are targeted against only a few immunodominant antigens, or are broadly distributed against a large range of antigens, and will therefore provide valuable information regarding the potential multivalency of candidate malaria vaccines. It is expected that the proposed research will have important outcomes for malaria vaccine development. It will identify novel P. falciparum antigens that should represent good candidates for a subunit malaria vaccine that would be effective in all human populations regardless of ethnicity. Additionally, data will demonstrate whether protective immune responses are targeted against only a few immunodominant antigens, or are broadly distributed against a large range of antigens, and will therefore provide valuable information regarding the potential multivalency of candidate malaria vaccines.