Identification of T-Cell Immunogens in Anaplasma

描述(由申请人提供)：由CD4+T淋巴细胞介导的MHC-II类限制性反应是无浆体科壁虱传播病原体的免疫控制的核心。针对细菌表面的高亲和力中和抗体的产生和有效的吞噬细胞激活导致细菌杀灭，需要启动和扩增CD4+T淋巴细胞。这项研究的目标是识别诱导免疫所需的T细胞反应的病原体蛋白。到目前为止，只有4个T细胞免疫刺激分子在边缘无浆体模式种中被鉴定出来，而在无浆体科中相关的人类病原体中没有发现。我们将通过一种全面的策略来解决这一知识差距，以确定外膜蛋白，这些外膜蛋白可以启动初始的CD4+T淋巴细胞，并诱导免疫和保护动物的回忆记忆T细胞反应。在项目的第一部分，我们建议结合外膜生化分级和基因组分析来确定T细胞反应的靶点。在第一部分的结束语中，我们希望能够鉴定出新的外膜蛋白，该外膜蛋白含有在边缘不动杆菌菌株中保守的CD4+T细胞表位。无浆体科物种间分子和免疫同源基因的存在表明，这些研究成果应该具有广泛的适用性，并加强对人类疾病的了解和控制。 在项目的第二部分，我们将研究在产生免疫中对共价相关外膜蛋白的连锁识别的要求。A.边缘外膜蛋白通过广泛的二硫键共价连接。这种共价键如何影响免疫力的产生尚不清楚。观察到主要表面蛋白(MSP)1a特异性的CD4+T细胞帮助B淋巴细胞分泌针对共价结合的MSPlb的抗体，这表明外膜蛋白的天然结合在诱导保护性反应中可能是关键的。我们假设，这种来自不同外膜蛋白的CD4+T细胞和B细胞表位的“连锁识别”可以使用嵌合的多表位结构来模拟。在第二部分的结论中，我们预计已经确定了以MSPla和MSPlb作为模型复合免疫原的共价结合外膜蛋白之间的连锁识别是否可以用嵌合表位构建来表示。

DESCRIPTION (provided by applicant): MHC class II-restricted responses mediated by CD4+ T lymphocytes are central to immune control of the tick-borne pathogens of the Family Anaplasmataceae. Priming and expansion of CD4+ T lymphocytes is required for development of high affinity neutralizing IgG antibodies directed against the bacterial surface and for efficient phagocyte activation leading to bacterial killing. The goal of the research is to identify the pathogen proteins that induce the T cell responses required for immunity. To date, only four T cell immunostimulatory molecules have been identified in Anaplasma marginale, the type species, and none in the related human pathogens within the Anaplasmataceae. We will address this knowledge gap using a comprehensive strategy to identify outer membrane proteins that prime naive CD4+ T lymphocytes and induce recall memory T cell responses of immunized and protected animals. In part 1 of the project, we propose to use a combination of biochemical fractionation of outer membranes combined with genomic analysis to identify the targets of the T cell response. At the conclusion of part 1, we expect to have identified novel outer membrane proteins bearing CD4+ T cell epitopes conserved among A. marginale strains. The presence of molecular and immunological orthologs among species in the Family Anaplasmataceae indicates that the research results should be broadly applicable and enhance understanding and control of human diseases. In part 2 of the project, we will examine the requirement for linked recognition of covalently associated outer membrane proteins in generating immunity. A. marginale outer membrane proteins are covalently linked by extensive disulfide bonding. How this covalent bonding affects generation of immunity is unknown. The observation that Major Surface Protein (MSP) 1a-specific CD4+ T cells provide help for B-lymphocytes to secrete antibody to the covalently bound MSPlb suggests that the native association of outer membrane proteins can be critical in inducing protective responses. We hypothesize that this "linked recognition" of CD4+ T cell and B cell epitopes from different outer membrane proteins can be mimicked using chimeric multiple epitope constructs. At the conclusion of part 2, we expect to have determined if linked recognition between covalently bound outer membrane proteins, using MSPla and MSPlb as a model complex immunogen, can be represented by a chimeric epitope construct.