Identifying the properties of LLO required for MHC class I presentation

确定 MHC I 类呈现所需的 LLO 的特性

• 批准号: 7629088
• 负责人: JODY A. MELTON-WITT
• 金额: $ 5.53万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7629088
• 关键词: Affect; Animal Cancer Model; Animals; Antigen Presentation Pathway; Biochemical; Biological; Biological Assay; CD4 Positive T Lymphocytes; CD8B1 gene; Cancer Vaccines; Cell surface; Cells; Cytosol; Defect; Engineering; Epitopes; Generations; Goals; Heterophile Antigens; Histocompatibility Antigens Class I; Immune; Immune response; Immune system; Immunity; Immunodominant Epitopes; In Vitro; Lead; Length; Listeria monocytogenes; Listeria monocytogenes hlyA protein; Location; MHC Class I Genes; Mediating; Metabolic; Modeling; Monitor; Mus; Mutagenesis; Mutation; Organism; Pathogenesis; Pathway interactions; Peptides; Phagosomes; Phosphorylation; Play; Process; Production; Property; Proteins; Regulation; Role; Series; T-Lymphocyte; Testing; Toxin; Tumor Antigens; Ubiquitination; Vaccines; antigen processing; base; cell mediated immune response; design; in vivo; multicatalytic endopeptidase complex; mutant; novel; pathogen; response; tumor; vector vaccine

DESCRIPTION (provided by applicant): Project Summary: Listeria monocytogenes (Lm) is a model intracellular pathogen that has been studied intensively to understand various aspects of the host's innate and cell-mediated immune responses. The induction of and acquired CD4 T cell response is crucial for protective immunity against this pathogen. A prerequisite for the induction of this protective immune response is escape from the primary phagosome into the cytosol where various components can be processed and presented in MHC class I molecules on the cell surface. Listeriolysin O (LLO) is a pore-forming toxin secreted by Lm and is required for escape from the phagosome. LLO also happens to be the protein from which the immunodominant epitope presented on MHC class I molecules is generated. Due to its intracellular location, the use of Lm as a vaccine vector for the delivery of tumor antigens to the cytosol where they can be processed and presented via MHC class I molecules is being heavily studied. Some of these studies have shown that fusion of LLO to the heterologous antigen will lead to the induction of a robust immune response that is otherwise not produced. It is the goal of this proposal to ascertain the properties of LLO that lead it through the MHC class I processing pathway and centers on the hypothesis that the natural properties of LLO that make it metabolically unstable and are essential for pathogenesis lead to its entry into the MHC class I processing pathway. To this end we will carry out the following two aims: 1) In vivo identification of residues that are essential for an immune response to LLO, and 2) In vitro characterization of the properties of LLO necessary for the generation of immunodominant epitopes. Relevance: Using Lm to deliver tumor antigens to the cytosol of host cells, it has been shown that the best immune response to established tumors is obtained when the tumor antigens are fused directly to LLO. Defining the properties of LLO that lead to such a strong immune response is the goal of this proposal with the hopes of using the information obtained in the design of more effective vaccines.

描述（由申请人提供）：项目摘要：单核细胞增生李斯特菌（Lm）是一种模型细胞内病原体，已被深入研究，以了解宿主的先天性和细胞介导的免疫反应的各个方面。诱导和获得性CD4 T细胞应答对于针对该病原体的保护性免疫至关重要。诱导这种保护性免疫应答的先决条件是从初级吞噬体逃逸到胞质溶胶中，在胞质溶胶中，各种组分可以被加工并呈递在细胞表面上的MHC I类分子中。李斯特菌溶血素O（LLO）是由Lm分泌的成孔毒素，并且是从吞噬体逃逸所必需的。LLO也恰好是产生MHC I类分子上呈递的免疫显性表位的蛋白质。由于其细胞内的位置，使用Lm作为疫苗载体用于将肿瘤抗原递送至细胞溶质，在细胞溶质中它们可以被加工并通过MHC I类分子呈递，正在进行大量研究。这些研究中的一些已经显示，LLO与异源抗原的融合将导致诱导否则不会产生的稳健的免疫应答。该提案的目标是确定LLO的性质，这些性质导致其通过MHC I类加工途径，并以LLO的天然性质导致其进入MHC I类加工途径的假设为中心，这些性质使其代谢不稳定并且对于发病机理至关重要。为此，我们将进行以下两个目标：1）对LLO的免疫应答所必需的残基的体内鉴定，和2）对产生免疫显性表位所必需的LLO的性质的体外表征。相关性：使用Lm将肿瘤抗原递送至宿主细胞的胞质溶胶，已经显示当肿瘤抗原直接融合至LLO时获得对已建立的肿瘤的最佳免疫应答。定义导致如此强烈的免疫应答的LLO的特性是该提案的目标，希望将获得的信息用于设计更有效的疫苗。