IMMUNE RECOGNITION OF CANDIDA--ROLE OF CELL WALL

描述(摘自申请者摘要)：病原真菌，例如 白色念珠菌作为机会性病原体越来越常见， 在免疫受损的宿主中引起显著的发病率和死亡率。 尽管真菌病原体的重要性与日俱增，但还有许多不重要的东西 了解它们的发病机制。具体地说，目前还不清楚如何 真菌病原体与先天免疫系统的细胞成分相互作用。 很可能是真菌病原体与先天的 免疫系统决定感染是否进一步发展为全身性感染。 葡聚糖是(1-3)-β-D连接的葡萄糖聚合物，是主要的 真菌细胞壁的碳水化合物组成。葡聚糖也被释放到 真菌感染患者的体循环。我们的工作 假说认为假丝酵母细胞壁(1-3)-β-D-葡聚糖在 免疫活性细胞--巨噬细胞与念珠菌的识别 中性粒细胞。为了批判性地评估这一假设，有四个具体的 目标。I.我们将从(1-3)-β-D-葡聚糖中分离和鉴定 假丝酵母细胞壁，来自假丝酵母菌丝的葡聚糖和 以胞外聚合物的形式释放到细胞外环境中。二、我们将对 受体介导的念珠菌结合/内化 (1-3)-β-D-葡聚糖在人巨噬细胞和中性粒细胞中的表达 葡聚糖受体(S)介导对念珠菌的摄取和/或杀伤。这些 研究还将解决假丝酵母葡聚糖是否 巨噬细胞表面CR3(CD11b/CD18)和/或Toll样受体识别 还有中性粒细胞。III.我们将研究念珠菌的体外作用 葡聚糖对转录调节蛋白(NFkB和NF-IL6)激活的影响 炎性细胞因子和趋化因子在人巨噬细胞中的表达 还有中性粒细胞。IV.我们将研究假丝酵母菌的体内效应 转录激活蛋白NFkB和NF-IL6上的(1-3)-β-D-葡聚糖， 免疫调节和炎症介质的表达与TH1/TH2的转换 以及假丝酵母葡聚糖是否能抵御真菌的挑战。我们会 还比较和对比了假丝酵母菌衍生葡聚糖和甘露聚糖在 以确定对这两者的反应是否有差异 真菌细胞壁的常见成分。我们的长期目标是 明确真菌细胞壁碳水化合物的细胞和分子机制 真菌感染的发病机制，并利用这些基础科学数据 确定潜在的药物靶点和/或改进的治疗策略 真菌败血症的治疗。

DESCRIPTION (Verbatim from Applicant's Abstract): Pathogenic fungi, such as Candida albicans, are increasingly common as opportunistic pathogens which cause significant morbidity and mortality in the immunocompromised host. Despite the growing significance of fungal pathogens there is much that is not known about their mechanisms of pathogenesis. Specifically, it is not clear how fungal pathogens interact with cellular components of the innate immune system. It is highly probable that the interaction of fungal pathogens with the innate immune system determines whether the infection proceeds to become systemic. Glucans are (1-3)-beta-D-linked polymers of glucose which are major carbohydrate constituents of fungal cell walls. Glucans are also released into the systemic circulation of patients with fungal infections. Our working hypothesis is that Candida cell wall (1-3)-beta-D-glucans play a major role in the recognition of Candida by immune competent cells, i.e. macrophages and neutrophils. To critically evaluate this hypothesis there are four specific aims. I. We will isolate and chemically characterize (1-3)-beta-D-glucans from Candida cell walls, glucans from Candida hyphae and the glucans which are released into the extracellular milieu as exopolymers. II. We will characterize the receptor mediated binding/internalization of Candida derived (1-3)-beta-D-glucans in human macrophages and neutrophils and determine whether the glucan receptor(s) mediate the uptake and/or killing of Candida. These studies will also address the questions of whether Candida glucans are recognized by the CR3 (CD11b/CD18) and/or Toll-like receptors on macrophages and neutrophils. III. We will investigate the in vitro effect of Candida glucans on activation of transcriptional regulatory proteins (NFkB and NF-IL6) and expression of inflammatory cytokines and chemokines in human macrophages and neutrophils. IV. We will investigate the in vivo effect of Candida derived (1-3)-beta-D-glucans on the transcriptional activator proteins NFkB and NF-IL6, expression of immunoregulatory and inflammatory mediators, TH1/TH2 switching and whether Candida glucans will protect against a fungal challenge. We will also compare and contrast the effects of Candida derived glucans and mannans in order to determine whether there are differences in response to these two common constituents of fungal cell walls. Our long-term objectives are to define the cellular and molecular mechanisms of fungal cell wall carbohydrates in the pathogenesis of fungal infections and to utilize this basic science data to identify potential drug targets and/or improved therapeutic strategies for the management of fungal sepsis.