Role of Mycobacterium tuberculosis protease in pathogenesis and host response

结核分枝杆菌是一种非常成功的人类病原体，它已经进化到在 主持人我们的长期目标是阐明M。结核病干扰了 巨噬细胞的杀微生物功能和逃避宿主免疫应答。了解分子 M.结核病-结核病相互作用对于设计治疗干预措施是重要的 疫苗策略。我们已经鉴定了Rv2224c，一种预测的蛋白酶，作为在哺乳动物中生存的关键。 巨噬细胞和体内。我们假设Rv2224c是一个重要的毒力因子， 劈裂M.结核病基质和调节宿主免疫应答。我们的初步研究 表明Rv2224c被输出到分枝杆菌的细胞包膜并分泌到细胞外。的突变 在蛋白酶中被破坏的蛋白质在巨噬细胞和体内的生长受到损害。感染蛋白酶的小鼠 突变体显示出显著降低肺病理学，且比野生型感染小鼠存活更长时间。在这 该提案将研究蛋白酶在宿主-病原体相互作用中的作用。具体目标是：1. Rv2224c及其潜在底物在M. 结核我们将研究Rv2224c在分枝杆菌中的定位，并进行结构-功能分析， Rv2224c的分析。我们将通过研究一种蛋白酶来研究其生物活性和特异性。 候选生理底物。2.研究蛋白酶与宿主免疫的相互作用 在巨噬细胞和体内的反应。我们将研究对Rv2224c的免疫应答的性质。 突变体，特别是确定T和B细胞在免疫中的作用，并进行结构-功能分析， 蛋白酶与宿主在巨噬细胞和体内的相互作用。3.巨噬细胞的调控机制 蛋白酶的功能。我们要问的是，感染突变体后， 应答，并测试Rv2224c：：tn突变体是否对IFN γ介导的免疫应答超易感。 应答最后，我们将研究Rv2224是否直接与宿主细胞组分相互作用， 互动研究

Mycobacterium tuberculosis is a highly successful human pathogen that has evolved to survive within the host. Our long-term goals are to delineate the mechanisms by which M. tuberculosis interferes with the microbicidal functions of macrophages and evades host immune responses. Understanding the molecular mechanisms underlying M. tuberculosis-}r\osi interactions is important for designing therapeutic interventions and vaccine strategies. We have identified Rv2224c, a predicted protease, as being critical for survival in macrophages and in vivo. We hypothesize that Rv2224c is an important virulence factor that proteolytically cleaves M. tuberculosis substrates and modulates the host immune response. Our preliminary studies indicate that Rv2224c is exported to the cell envelope of mycobacteria and secreted extracellularly. A mutant disrupted in the protease is impaired for growth in macrophages and in vivo. Mice infected with a protease mutant show markedly reduced lung pathology and survive longer than wildype-infected mice. In this proposal will study the role of the protease in host-pathogen interactions. The specific aims are: 1. Molecular and biochemical characterization of Rv2224c and its potential substrate(s) in M. tuberculosis. We will study the localization of Rv2224c in mycobacteria and perform structure-function analysis of Rv2224c. We will investigate the biological activity and specificity of the protease by studying a candidate physiologic substrate. 2. Study the interaction of the protease with the host immune response in macrophages and in vivo. We will examine the nature of the immune response to Rv2224c mutant, specifically determine the role of T and B cells in immunity and perform structure-function analysis of protease interaction with the host in macrophages and in vivo. 3. Dissect the modulation of macrophage function by the protease. We will ask whether infection with the mutant elicits altered macrophage responses and test whether the Rv2224c::tn mutant is hyper-susceptible to IFNy-mediated immune responses. Finally, we will study whether Rv2224 directly interacts with host cell components using proteinprotein interaction studies.