Antigen processing and presentation of recombinant Listeria proteins

重组李斯特菌蛋白的抗原加工和呈递

• 批准号: 7978828
• 负责人: Michael F. Princiotta
• 金额: $ 19.75万
• 依托单位: UPSTATE MEDICAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7978828
• 关键词: Affect; Antigen Presentation; Antigen Presentation Pathway; Antigen-Presenting Cells; Antigens; Attenuated; Bacteria; Bacterial Proteins; CD8-Positive T-Lymphocytes; CD8B1 gene; Cancerous; Catalytic Domain; Cell surface; Cells; Cellular Immunity; Chemicals; Cross Presentation; Cytosol; Effector Cell; Employee Strikes; Exposure to; Generations; Goals; Half-Life; Histocompatibility Antigens Class I; Immune; Immune response; Infection; Knowledge; Lead; Life; Life Style; Listeria; Listeria monocytogenes; Listeriosis; MHC Class I Genes; Mammalian Cell; Mediating; Molecular; Organism; Parasites; Pathway interactions; Pattern recognition receptor; Peptide/MHC Complex; Peptides; Play; Process; Production; Proteins; Publishing; Recombinant Proteins; Recombinants; Role; Surface; T cell response; T-Cell Receptor; T-Lymphocyte; Testing; Tissues; Tumor Antigens; Tumor-Derived; Vaccination; Vaccines; Vaccinia virus; Vesicle; Viral; Viral Proteins; Virus; antigen processing; bacterial vector; cancer cell; cell mediated immune response; cell type; design; inhibitor/antagonist; neoplastic cell; null mutation; numb protein; pathogen; public health relevance; tumor; vector; vector vaccine

DESCRIPTION (provided by applicant): CD8+ T lymphocytes are the primary immune effector cells that respond to many intracellular pathogens, including viruses, bacteria and parasites, as well as tumors. To recognize infected or neoplastic cells, CD8+ T cells must first be primed by interacting through their T cell receptor with peptide-MHC (pMHC) complexes displayed on the surface of professional antigen presenting cells (pAPC). This can occur either through natural exposure to the pathogen or tumor antigen or by intentionally introducing protein to the antigen processing machinery of a pAPC, as is done during vaccination. One of the most effective ways to introduce proteins for the purpose of priming a CD8+ T cell response is to express that protein using a live, attenuated vector such as the intracellular bacterium, Listeria monocytogenes. Because Listeria enters the host cell cytosol within minutes after initial infection, proteins secreted by the bacterium are readily accessible to the host cell's antigen processing machinery, making Listeria a particularly effective vector for eliciting CD8+ T cell responses. Therefore, we have been investigating the mechanisms involved in the processing of recombinant Listeria proteins for presentation on MHC class I molecules. Our recent studies have uncovered a striking difference in the way recombinant Listeria antigens are processed and presented when compared to endogenously synthesized proteins. Specifically, we have found that pMHC production from secreted Listeria proteins occurs at the same rate, independent of the cellular half-life of the protein from which it is derived. It is our hypothesis that these differences in processing and presentation reflect real differences in the cellular machinery responsible for the degradation of endogenously synthesized proteins vs. exogenously derived bacterial proteins. The studies we propose in this application will focus on determining what factors contribute these differences in processing. We will do this by 1) determining whether differences in protein half-life and processing efficiency are dependent on the endogenous protein processing machinery of the cell and 2) establishing the role Listeria localization plays in determining the processing pathway followed by secreted recombinant proteins. Our studies should provide us with a more detailed understanding of the mechanisms involved in class I antigen processing and presentation. PUBLIC HEALTH RELEVANCE: These studies should increase our understanding of the mechanisms of antigen processing and presentation of proteins expressed using an intracellular bacterial pathogen as a vector. How proteins are degraded and presented in infected cells can impact the quality and magnitude of the cellular immune response. This knowledge is critical to our understanding of how cellular immunity is elicited to antigenic proteins derived from pathogenic organisms and malignant cells. It is expected that this knowledge will aid in the design of effective vaccines.

描述（由申请人提供）： CD 8 + T淋巴细胞是对许多细胞内病原体（包括病毒、细菌和寄生虫以及肿瘤）作出应答的主要免疫效应细胞。为了识别感染或肿瘤细胞，CD 8 + T细胞必须首先通过其T细胞受体与专业抗原呈递细胞（pAPC）表面上展示的肽-MHC（pMHC）复合物相互作用来引发。这可以通过自然暴露于病原体或肿瘤抗原或通过有意地将蛋白质引入pAPC的抗原加工机制来发生，如在疫苗接种期间所做的那样。为了引发CD 8 + T细胞应答而引入蛋白质的最有效的方法之一是使用活的减毒载体（例如细胞内细菌单核细胞增生李斯特菌）表达该蛋白质。由于李斯特菌在初始感染后几分钟内进入宿主细胞胞质溶胶，因此细菌分泌的蛋白质容易进入宿主细胞的抗原加工机制，使李斯特菌成为引发CD 8 + T细胞应答的特别有效的载体。因此，我们一直在研究重组李斯特菌蛋白质的加工机制，以呈递MHC I类分子。 我们最近的研究发现，与内源性合成的蛋白质相比，重组李斯特菌抗原的加工和呈递方式存在显著差异。具体地，我们已经发现，从分泌的李斯特菌蛋白产生pMHC以相同的速率发生，与其所来源的蛋白的细胞半衰期无关。我们的假设是，这些加工和呈递的差异反映了内源性合成蛋白质与外源性来源的细菌蛋白质降解的细胞机制的真实的差异。我们在本申请中提出的研究将集中在确定哪些因素导致这些差异的处理。我们将通过1）确定蛋白质半衰期和加工效率的差异是否取决于细胞的内源性蛋白质加工机制和2）确定李斯特菌定位在确定分泌的重组蛋白随后的加工途径中所起的作用来实现这一点。我们的研究应该为我们提供了一个更详细的了解的机制，参与第一类抗原的加工和介绍。 公共卫生关系：这些研究应增加我们的抗原加工和使用细胞内细菌病原体作为载体表达的蛋白质的呈递的机制的理解。蛋白质在感染细胞中的降解和呈递方式会影响细胞免疫反应的质量和程度。这些知识对于我们理解细胞免疫是如何对来自病原生物和恶性细胞的抗原蛋白引起的至关重要。预计这些知识将有助于设计有效的疫苗。