Inhibiting F. tularensis Adherence to Alveolar Type II Cells as a Vaccine Strateg

摘要 土拉热弗朗西丝菌是一种潜在的生物武器，它具有易于繁殖、宿主范围广、传播途径多样和毒力强等特点。最高的发病率和死亡率与吸入氟中毒引起的肺性土拉菌病有关。土拉热。我们发现吸入F.与肺泡II型（ATII）上皮细胞相关土拉热菌和转座子 在吸入感染模型中，侵入但不在ATII细胞内复制的插入突变体显著减弱。细胞结合试验结果表明，F.土拉菌表达一种预先形成的粘附素，可介导体外ATII细胞的附着和侵袭。介导AT-II细胞粘附和侵袭的细菌配体将通过筛选F.土拉热菌基因组文库 在大肠杆菌中表达杆菌通过用全F. tularensis细菌，我们发现F.土拉热菌特异性结合聚糖阵列上的Mana 1 -6（Mana 1 -3）Mana 1 -6（Mana 2 Mana 1 -3）Man <$1 - 4GlcNAc <$1 - 4GlcNAc <$-Sp12，平均荧光强度单位为3766 ± 94，变异系数为2%，表明结合既特异又显著。我们正在努力确定与这种复合碳水化合物结合在F.土拉菌毒力和致病性。

Abstract The bacterial pathogen Francisella tularensis is a potential biological weapon by virtue of its ease of propagation, broad host range, myriad of transmission routes and extraordinary virulence. The highest morbidity and mortality is associated with pneumonic tularemia initiated by inhalation of F. tularensis. We found that inhaled F. tularensis associate within alveolar Type II (ATII) epithelial cells, and a transposon insertion mutant that invades, but does not replicate within, ATII cells was significantly attenuated in an inhalation model of infection. Results from cell association assays demonstrated that F. tularensis expressed a pre-formed adhesin that mediates attachment and invasion of ATII cells in vitro. The bacterial ligand(s) that mediate AT-II cell adherence and invasion will be identified by screening F. tularensis genomic libraries expressed in E. coli. Through probing of glycan arrays with whole F. tularensis bacteria we found that F. tularensis bound specifically to Mana1-6(Mana1-3)Mana1-6(Mana2Mana1-3)Man¿1-4GlcNAc¿1-4GlcNAc¿-Sp12 on the glycan ¿ array at an average of 3766 + 94 fluorescence intensity units with a 2% coefficient of variance suggesting that the binding was both specific and significant. We are working to determine the role that binding to this complex carbohydrate plays in F. tularensis virulence and pathogenesis.