Cell wall protein in Bacillus anthracis pathogenesis

描述（由申请人提供）：炭疽热是一种古老的疾病，对科学家和公众都有重生的意义。为了对抗这个老敌人，必须在其发病机制的分子水平上清楚和充分地了解致病生物，即炭疽芽孢杆菌。许多革兰氏阳性致病菌具有细胞壁锚定蛋白（CWAPs），对毒力至关重要，是极好的候选疫苗。通过类比，炭疽杆菌的cwap可能会显示出同样的相关性和效用。对炭疽杆菌基因组的分析揭示了9个以前未表征的cwap。初步研究表明，这些识别特异性巨噬细胞靶点之一的重组片段。巨噬细胞在炭疽的形成中起着核心作用。另外两个cwap被发现与胶原蛋白结合，胶原蛋白是皮肤炭疽发生的主要成分。总之，这些发现支持了炭疽杆菌的CWAPs在其发病机制中起重要作用的假设。

DESCRIPTION (provided by applicant): Anthrax is an old disease with re-born relevance to both scientists and public. To fight this old foe, the causative organism, Bacillus anthracis, must be understood clearly and fully at the mechanistic molecular level of its pathogenesis. Many Gram-positive pathogenic bacteria possess cell wall anchored proteins (CWAPs) that are critical for virulence and are excellent vaccine candidates. By analogy, the CWAPs of B. anthracis are likely to show equal relevance and utility. Analysis of the B. anthracis genome revealed nine previously uncharacterized CWAPs. Preliminary studies indicated a recombinant fragment of one of these recognized specific macrophage targets. Macrophages play a central role in the establishment of anthrax. Two additional CWAPs were found to bind collagen, which is a major component of the skin where cutaneous anthrax develops. Together these findings support the hypothesis that CWAPs of B. anthracis are significant in its pathogenesis. The two specific aims of this proposal are to determine the roles of CWAPs in the interaction of B. anthracis with 1) macrophages and 2) major skin components i.e., collagen and fibroblasts. To achieve these aims, deletion mutants will be generated for each of the nine CWAPs. The mutants will be evaluated for their ability to associate with, be engulfed by and survive within macrophages, as well as their ability to adhere and invade human dermal fibroblasts. The respective mutants will also be used to determine the relevance of each of the two collagen-binding CWAPs in the adherence of B. anthracis to collagen. To confirm the function of the CWAPs, the deleted genes will be complemented then expressed in a heterologous host. Their molecular targets in the host cells will subsequently be identified. In the future, the effect of these proteins in B. anthracis virulence will be evaluated in an animal model in collaboration with Dr. Theresa Koehler at University of Texas Medical School, and Dr. Rick Lyons at University of New Mexico. The long-term objectives are to elucidate the biological functions of these proteins, their molecular interactions with the host and their potential as vaccine and drug targets. The information will likely improve the understanding of the infection mechanisms of B. anthracis, and may provide novel effective ways to combat the scourge of anthrax.