慢生长分枝杆菌LprA氨基端序列多态性对蛋白功能的影响及其诊断价值研究

结核病（TB）严重影响公众健康，而非结核分枝杆菌（NTM）病发病率上升增加了TB控制的复杂性。临床缺乏TB与NTM病的鉴别诊断技术，尤其是未获得病原菌的“菌阴”患者，尚无技术能实现NTM病的诊断及菌种鉴定。基于前期研究结果和文献调研，我们发现：脂蛋白是结核杆菌致病性关键因子，不同种分枝杆菌培养滤液中脂蛋白表达水平差异明显，而临床常见的慢生长分枝杆菌（SGM）LprA蛋白氨基端序列差异显著（同源性仅45-50%）。本研究拟利用LprA蛋白序列多样性分别开发用于培养滤液和患者血清的快速、简便的SGM菌种鉴定方法，实现对“菌阴”患者诊断的突破。同时，还将研究LprA蛋白氨基端差异对蛋白细菌胞内定位、刺激免疫细胞活化及抑制抗原呈递等功能的影响，观察表达不同菌种来源LprA蛋白的细菌在巨噬细胞内生存能力，了解LprA蛋白在不同种SGM的免疫原性和致病性方面的作用，为阐明不同菌种致病性差异提供线索。

Tuberculosis remains a serious threat to public health, whereas the increased epidemiological tendency of non-tuberculous mycobacteria (NTM) disease complicates the TB control. There is unmet demands for TB and NTM differentiating diagnosis, furthermore, now it is impossible for differentiation when patients have no bacteria available. Based on our preliminary works and the published literatures, we found that lipoprotein is a major virulence factor of Mycobacteria tuberculosis. Different mycobacterial species have very different expression levels of lipoprotein, and different pathogenic slow-growing mycobacteria (SGM) have highly variable N-terminal amino acid compositions (45-50% identify between each other) in their LprA lipoprotein. We plan to harness this very specific characterization by developing immunological tools, so as to differentiate different SGM species in broth of positive culture or serum of patient with mycobacterial infection, rapidly and conveniently. There is possibility that this tool could be used for bacteria-negative patient as well .Meanwhile, we will elucidate the influence of the N-terminal variance of LprA on protein location and function. The purpose of this study is to intensify the understanding of the value of lipoprotein onl virulence and immunity of different mycobacteria species, and to provide clues to identify the mechanism that causes the great pathogenicity difference of species within mycobacterium genus.