Studies on Macrophage Resistance to Anthrax Lethal Toxin

性状（由申请方提供）：致死毒素是炭疽芽孢杆菌的主要毒力因子。 致死毒素（LT）由保护性抗原（PA）和致死因子（LF）两种蛋白质组成。 巨噬细胞是抵御炭疽感染的第一道防线。 小鼠品系和衍生自这些品系的原代巨噬细胞或巨噬细胞系对致死性毒素介导效应的敏感性存在显著差异。 某些小鼠品系和它们的巨噬细胞对LT敏感，而其他小鼠品系和它们的巨噬细胞对LT具有高度抗性。抗性的潜在机制仍然未知，并且由于这些信息对开发治疗方法的潜在有用性，因此在炭疽领域是一个非常感兴趣的主题。 本项目的主要目的是研究巨噬细胞对LT的抵抗机制。 为实现这一目标，提出了三个具体目标：（1）使用免疫荧光/共聚焦显微镜研究细胞运输和定位的改变，以检查LF在敏感与抗性巨噬细胞中的定位，（2）研究潜在LF细胞内底物在抗性巨噬细胞中的作用，和（3）差异微阵列分析的分析，以评价LT敏感性与抗性巨噬细胞中的基因表达，重点是评价细胞因子表达，MAPK激酶效应分子表达，和表达Kif 1C，最近描述的小鼠基因产物与LT的抗性。这些研究的成功完成将产生巨噬细胞LT抗性机制的基本理解。

DESCRIPTION (provided by applicant): Lethal toxin is a major virulence factor of Bacillus anthracis. Lethal toxin (LT) is comprised of two proteins, protective antigen (PA) and lethal factor (LF). Macrophages serve as the first line of defense against anthrax infection. There is a striking difference in susceptibility of mouse strains and the primary macrophages or macrophage cell lines derived from those strains to lethal, toxin-mediated effects. Certain mouse strains and their macrophages are sensitive to LT whereas other mouse strains and their macrophages are highly resistant to LT. The underlying mechanism of resistance remains unknown and is a subject of great interest in the anthrax field due to the potential usefulness of this information to development of therapeutics. The primary goal of this project is to investigate mechanisms of resistance to LT in macrophages. To address this goal, three specific aims are proposed: (1) Investigation of alterations in cellular trafficking and localization using immunofluorescence/confocal microscopy to examine localization of LF in sensitive versus resistant macrophages, (2) Investigation of the role of potential LF intracellular substrates in resistant macrophages, and (3) Analysis of differential microarray analyses to evaluate gene expression in LT-sensitive versus resistant macrophages with a focus on evaluating cytokine expression, MAPK kinase effector molecule expression, and expression of Kif1C, a recently described murine gene product associated with resistance to LT. Successful completion of these studies will yield a fundamental understanding of mechanisms of macrophage resistance to LT.