Ronander Elena, Brant Marta, Janson Håkan, Sheldon Joanna, Forsgren Arne, Riesbeck Kristian
Medical Microbiology, Department of Laboratory Medicine, Malmö University Hospital, Lund University, SE-205 02 Malmö, Sweden.
Microbes Infect. 2008 Jan;10(1):87-96. doi: 10.1016/j.micinf.2007.10.006. Epub 2007 Oct 22.
Non-typable Haemophilus influenzae (NTHi) is an important human-specific respiratory pathogen colonizing the mucosa of the upper respiratory tract. The bacterium is a common cause of acute otitis media in children and exacerbations in patients with chronic obstructive pulmonary disease (COPD). An immunoglobulin (Ig) D-lambda myeloma protein was found to detect a 16 kDa surface protein that we designated protein E (PE). The pe gene was cloned using an NTHi genomic DNA library, and a truncated PE-derived protein lacking the endogenous signal peptide (PE22-160) was synthesized and produced in large amounts in Escherichia coli. Interestingly, PE was expressed at the bacterial surface of NTHi as revealed by flow cytometry using the IgD-lambda myeloma protein or PE-specific polyclonal antibodies. A PE-deficient NTHi mutant was produced and lost 50% of its adhesive capacity as compared to the wild-type counterpart when analysed for adhesion to type II lung alveolar epithelial cells. In parallel, E. coli expressing full-length PE1-160 adhered significantly more efficiently to epithelial cells as compared to wild-type E. coli. Recombinant IgD that recognized the chemical dansyl-chloride did not interact with PE indicating that the IgD-lambda myeloma protein most likely was an antibody directed against the H. influenzae surface epitope. In conclusion, we have discovered a novel NTHi outer membrane protein with adhesive properties using an IgD-myeloma protein.
不可分型流感嗜血杆菌（NTHi）是一种重要的人类特异性呼吸道病原体，定殖于上呼吸道黏膜。该细菌是儿童急性中耳炎以及慢性阻塞性肺疾病（COPD）患者病情加重的常见病因。发现一种免疫球蛋白（Ig）D-λ骨髓瘤蛋白可检测到一种16 kDa的表面蛋白，我们将其命名为蛋白E（PE）。利用NTHi基因组DNA文库克隆了pe基因，并合成了一种缺少内源性信号肽的截短型PE衍生蛋白（PE22-160），并在大肠杆菌中大量生产。有趣的是，使用IgD-λ骨髓瘤蛋白或PE特异性多克隆抗体通过流式细胞术显示，PE在NTHi的细菌表面表达。构建了一个PE缺陷型NTHi突变体，在分析其对II型肺泡上皮细胞的黏附时，与野生型相比，其黏附能力丧失了50%。同时，与野生型大肠杆菌相比，表达全长PE1-160的大肠杆菌对上皮细胞的黏附效率明显更高。识别化学丹磺酰氯的重组IgD不与PE相互作用，这表明IgD-λ骨髓瘤蛋白很可能是一种针对流感嗜血杆菌表面表位的抗体。总之，我们利用一种IgD-骨髓瘤蛋白发现了一种具有黏附特性的新型NTHi外膜蛋白。
