解脲脲原体多带抗原（MBA）的高毒力片段筛选及致病机制研究

解脲脲原体（Ureaplasma spp.）可引起泌尿生殖道多种感染性疾病，严重影响人类生殖健康。现有研究表明，解脲脲原体的致病机制与其携带的多种毒力因子密切相关，而多带抗原（Multiple banded antigen, MBA）被认为是解脲脲原体的主要毒力因子之一。本课题组前期通过对解脲脲原体临床菌株和标准菌株的比较基因组学分析发现，大多数毒力因子的基因序列较为保守，而MBA在不同菌株间存在较大差异，但其致病机制与生物学功能目前尚未阐明。本研究拟通过细胞粘附试验筛选出高粘附力MBA蛋白，进一步通过基因敲除技术，构建mba缺失株。在细胞水平比较mba缺失株与野生株的毒力差异，从而进一步筛选高毒力MBA蛋白，并应用冷冻电镜技术解析高毒力MBA蛋白三维结构。本研究可为建立基于MBA毒力因子检测的致病性解脲脲原体临床诊断新技术奠定基础，极可能为区分解脲脲原体定植与感染提供科学依据。

Ureaplasma spp. can cause a variety of infectious diseases in the genitourinary tract and seriously affect human reproductive health. The pathogenesis of Ureaplasma spp. is closely related to its virulence factor, the multiple banded antigen (MBA) is the main virulence factor of Ureaplasma spp. The comparative genomics analysis of clinical Ureaplasma strains and American Type Culture Collection strains revealed that most virulence factors of Ureaplasma spp. were conservative, while MBA showed great differences among Ureaplasma strains. In this study, the MBA proteins with high adhesion will be initially screened out and then the corresponding genes of the screened proteins will be deleted by gene knockout. The role of the deleted genes on the pathogenicity of strains will be studied at cellular level. Based on the virulence experiments, the highly toxic MBA proteins will be screened out and the structure of them will be analyzed using cryo-electron microscopy. The aim of this study was to establish a novel clinical diagnostic technology for pathogenic Ureaplasma spp. based on the MBA and it is also likely to provide a new clue to differentiate Ureaplasma colonization and infection.