Novel Linear Peptide Universal Malaria Vaccines

描述（由申请方提供）：本项目的广泛长期目标是评价含有疟原虫通用T细胞表位和免疫显性B细胞表位的合成线性肽嵌合体（LPC）作为有效疟疾疫苗组分的潜力。我们建议研究一系列混杂的T细胞表位，我们已经确定在两个间日疟原虫裂殖子蛋白。这些推定的通用T细胞表位通过使用可溶性DRB 1 * 分子的体外肽结合测定来鉴定。分别测试了代表两种蛋白质的整个氨基酸序列的合成肽组。通过设计含有来自两种表征的蛋白质之一的单个T细胞表位和来自恶性疟原虫环子孢子（CS）蛋白的NANP重复序列的LPC，作为用于这些评价的标准B细胞表位，来证实用混杂T细胞表位免疫诱导的辅助活性。非常高的抗肽和抗寄生虫抗体和细胞抗肽Th 1和Th 2细胞因子的档案后，引发免疫与整个组的测试结构。此外，对NANP序列的遗传限制在典型的无应答BALB/c小鼠中被克服。重要的是，LPC免疫诱导的抗体也能够抑制活子孢子侵入人肝细胞。我们现在的目标是进一步研究这种方法在亚单位疟疾疫苗设计的体内相关性。新的肽构建体将被设计为含有其他混杂T细胞表位，从我们已经鉴定的那些中选择，并在具有不同遗传背景的小鼠中测试免疫原性。我们假设这些混杂T细胞表位中的一些实际上是通用T细胞表位，因为它们能够结合几种MHC II类分子。用于设计多聚体和多物种构建体的LPC方法的简单性促进了几个变量的筛选，包括：一种以上T细胞表位的物理结合，特定T细胞表位对免疫应答向Th 1或Th 2表型极化的内在活性，不同B细胞表位的包含，以及辅助性T细胞活性所需的最小T细胞表位的定义。这些研究将为设计和测试选定的基于疟原虫的LPC在恒河猴（一种接近人类的动物模型）中的有效性奠定基础。将在肽结合试验中评价潜在LPC免疫原结合Mamu-DR等位基因的能力，然后在实验感染食蟹猴疟原虫和Coatneyi疟原虫的猴中评价免疫原性和回忆应答：分别为间日疟原虫和恶性疟原虫的猴疟疾模型。这些方法将提供强有力的数据来评估LPC方法作为临床试验的前进方向，无论是单独使用还是与其他疟疾疫苗平台组合使用。

DESCRIPTION (provided by applicant): The broad long-term objective of this project is to evaluate the potential of synthetic linear peptide chimeras (LPCs) containing Plasmodium universal T cell epitopes and immunodominant B cell epitopes as effective malaria vaccine components. We propose to study a series of promiscuous T cell epitopes that we have identified in two Plasmodium vivax merozoite proteins. These putative universal T cell epitopes were identified by using in vitro peptide-binding assays to soluble DRB1* molecules. Sets of synthetic peptides, representing the entire amino acid sequences of both proteins, were individually tested. Helper activity induced by immunization with promiscuous T cell epitopes was confirmed by designing LPCs containing individual T cell epitopes from one of the two characterized proteins and the NANP repeat sequence from the P. falciparum circumsporozoite (CS) protein, as a standard B cell epitope for these evaluations. Very high antipeptide and antiparasite antibodies and cellular anti-peptide Th1 and Th2 cytokine profiles were elicited after immunization with the entire group of constructs tested. Further, genetic restriction to the NANP sequence was overcome in the typically non-responder BALB/c mouse. Importantly, the antibodies elicited by the LPC immunizations were also able to inhibit the invasion of viable sporozoites to human hepatocytes. We now aim to investigate further the in vivo relevance of this approach for the design of subunit malaria vaccines. New peptide constructs will be designed containing other promiscuous T cell epitopes, selected from those we have identified, and tested for immunogenicity in mice with diverse genetic backgrounds. We hypothesize that a number of these promiscuous T cell epitopes are in fact universal T cell epitopes for their ability to bind several MHC class II molecules. The simplicity of the LPC method for designing multimeric and multispecies constructs facilitates the screening of several variables including: the physical association of more that one T cell epitope, the intrinsic activity of the particular T cell epitopes on the polarization of the immune response towards a Th1 or Th2 phenotype, the inclusion of different B cell epitopes, and the definition of minimal T cell epitopes required for T helper cell activity. These studies will form the foundation for designing and testing the effectiveness of selected Plasmodium-based LPCs in rhesus monkeys, an animal model close to humans. Potential LPC immunogens will be evaluated in peptide-binding assays for their ability to bind Mamu-DR alleles, and then for immunogenicity and recall responses in monkeys experimentally infected with P. cynomolgi and P. coatneyi: simian malaria models for P. vivax and P. falciparum, respectively. These approaches will provide strong data to evaluate the LPC approach as a ways forward for clinical trials, whether used singly or in combination with other malaria vaccine platforms.