EPITOPE DELIVERY, IMMUNODOMINANCE AND VACCINE EFFICACY

描述（改编自申请人的摘要）：对L.单核细胞增多症用于研究对细胞内细菌的细胞介导的免疫的一般特征。在BALB/c小鼠中，已经分离出李斯特菌特异性的CD 8 + CTL，其是Kd限制性的。来自嗜酸乳杆菌溶血素O（LLO）（一种在吞噬泡中分泌的分子）和p60（一种在细胞质中大量分泌的分子）的肽已被鉴定为CTL靶标。CTL频率分析表明，LLO衍生的决定簇LLO 91-99是免疫显性的。我们推测，吞噬泡内的LLO分泌是LLO 91-99肽的免疫优势的一个促成因素。在特定目标I中，描述了将确定吞噬泡内的定义肽的分泌是否是其免疫优势的促成因素的研究。对于这些研究，我们将使用L。单核细胞增多症突变体，其中Kd结合纳米聚体肽内2位的锚残基（通常为酪氨酸）已被苯丙氨酸取代。突变体保留野生型表型，但在用这些菌株免疫后，特异性CTL不被刺激至突变体肽序列。我们将利用这些突变体将李斯特菌衍生的特异性肽递送到李斯特菌的吞噬泡或细胞质中。为了确定这些初始位置对随后的CTL应答的影响，需要对单核细胞增多性感染的细胞进行标记。L.单核细胞增多症已被提议作为递送候选抗原和刺激特异性细胞介导的免疫的载体。用于递送候选抗原的疫苗载体的价值部分取决于在现有抗载体免疫的环境中特异性刺激免疫应答的能力。在具体目标II中，我们将确定L的效用。本发明的目的是提供单核细胞增多症作为疫苗载体的方法，并评估肽特异性免疫力在对疫苗载体具有确定水平的现有免疫力的动物中的发展。我们将评估肽特异性效应细胞和记忆细胞反应的发展。这些研究的结果将指导新型疫苗载体的一般开发策略，以及确定其在疫苗载体免疫状态未知的人群中的使用限制。

DESCRIPTION (adapted from applicant's abstract): The protective immune response to L. monocytogenes is used to investigate general features of cell-mediated immunity to intracellular bacteria. In BALB/c mice, Listeria-specific CD8+ CTL have been isolated which are Kd restricted. Peptides from listeriolysin O (LLO) a molecule secreted in the phagocytic vacuole, and p60, a molecule that is abundantly secreted in the cytoplasm, have been identified as CTL targets. CTL frequency analysis shows that the LLO-derived determinant, LLO 91-99, is immunodominant. We hypothesize that secretion of LLO within the phagocytic vacuole is a contributing factor to the immunodominance of the LLO 91-99 peptide. In Specific Aim I, studies are described that will determine if secretion of defined peptides within the phagocytic vacuole is a contributing factor to their immunodominance. For these studies, we will use L. monocytogenes mutants in which the anchor residue at position 2 within the Kd-binding nanomer peptide (normally a tyrosine) has been replaced by phenylalanine. The mutants retain the wildtype phenotype, yet following immunization with these strains, specific CTL are not stimulated to the mutant peptide sequence. We will use these mutants to deliver specific Listeria-derived peptides to the phagocytic vacuole or the cytoplasm of the L. monocytogenes infected cell in order to determine the influence of these initial locations on the subsequent CTL response. L. monocytogenes has been proposed as a vector to deliver candidate antigens and stimulate specific cell-mediated immunity. The value of vaccine vectors for delivery of candidate antigens depends in part on the ability to specifically stimulate the immune response in an environment of existing anti-vector immunity. In Specific Aim II, we will determine the utility of L. monocytogenes as a vaccine vector and assess the development of peptide specific immunity in animals that have defined levels of existing immunity to the vaccine vector. We will assess the development of peptide specific effector cell and memory cell responses. The results from these studies will guide strategies for the general development of novel vaccine carriers as well as to define the limits of their use within a population whose immunologic status to the vaccine carrier is unknown.