Phase variation with altering phosphorylcholine expression of nontypeable Haemophilus influenzae affects bacteria clearance and mucosal immune response in the middle ear and nasopharynx
Phase variation with altering phosphorylcholine expression of nontypeable Haemophilus influenzae affects bacteria clearance and mucosal immune response in the middle ear and nasopharynx
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DOI：
10.1016/j.anl.2020.07.001
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发表时间：
2021-02-04
影响因子：
1.7
通讯作者：
Suzuki, Masashi
中科院分区：
文献类型：
--
作者：
Kadowaki, Yoshinori;Hirano, Takashi;Suzuki, Masashi
目的：不可分型流感嗜血杆菌（NTHi）是急性中耳炎和渗出性中耳炎的主要病原体。磷酸胆碱(ChoP)表达于脂寡糖上，且ChoP具有相位变异，这与其对上呼吸道上皮细胞的粘附和侵袭有关。然而，人们对 ChoP 表达的作用知之甚少。我们通过比较中耳和鼻部攻击小鼠模型中的 ChoP(+) 和 ChoP(-) 菌株，研究了 NTHi 从鼻子和中耳的粘膜清除动力学以及对 NTHi 感染的粘膜免疫反应。 方法：对 6 周龄的雄性 BALB/c 小鼠进行中耳和鼻咽部细菌攻击。给小鼠接种 NTHi 的 ChoP(+) 菌株或 ChoP(-) 菌株的悬浮液。接种后第1、3和7天，从各组中收集中耳洗液(MEW)和鼻洗液(NW)。样品用于细菌计数，上清液用于测定细胞因子和C反应蛋白（CRP）水平。结果：ChoP（+）菌株组的MEW在第1天的细菌计数明显高于ChoP（-）菌株组。但在第7天，ChoP（+）菌株组的细菌被根除。ChoP（+）菌株组的NWs的细菌计数高于ChoP（-）菌株组的NWs。然而实验过程中ChoP(-)菌株组，两种菌株之间没有显着差异。 MEWs中ChoP(-)株组的细胞因子水平显着高于ChoP(+)株组，但NWs中这些细胞因子水平较低。在 MEW 中，ChoP(-) 组的 CRP 浓度在第 7 天较高。在NWs中，实验期间各组CRP浓度均较低。结论：NTHi的ChoP表达改变了对CRP杀伤敏感的生物体，ChoP(+)菌株可能通过CRP补体级联逐渐从中耳根除，但不能从鼻咽根除。根据我们的研究结果，通过改变不可分型流感嗜血杆菌的磷酸胆碱表达而产生的相位变化会影响中耳和鼻咽部的细菌清除和粘膜免疫反应。 (c) 2020 日本耳鼻喉科协会 (Oto-Rhino-Laryngological Society of Japan Inc.) 由 Elsevier B.V. 出版。保留所有权利。
Objectives: Nontypeable Haemophilus influenzae (NTHi) is a chief pathogen in both acute otitis media and otitis media with effusion. Phosphorylcholine (ChoP) is expressed on lipooligosaccharides, and ChoP has phase variation, which is related to its adhesion to and invasion of epithelial cells in the upper airway. However, little is known about the role of ChoP expression. We examined the kinetics of the mucosal clearance of NTHi from the nose and middle ear and the mucosal immune response to NTHi infection by comparing ChoP(+) and ChoP(-) strains in a mouse model of middle ear and nasal challenge.Methods: Six-week-old male BALB/c mice were subjected to bacterial challenge in the middle ear and nasopharynx. Mice were inoculated with a suspension of a ChoP(+) strain or ChoP(-) strain of NTHi. On days 1, 3, and 7 after inoculation, the middle ear wash (MEW) and nasal wash (NW) were harvested from each group. The samples were used for bacterial counts and the supernatant was used to measure the level of cytokines and C-reactive protein (CRP).Results: MEWs in the ChoP(+) strain group had significantly higher bacterial counts than those in the ChoP(-) strain group on day 1. However, bacteria were eradicated in the ChoP(+) strain group on day 7. NWs in the ChoP(+) strain group had higher bacterial counts than those in the ChoP(-) strain group during the experiment, however, there was no significant difference between the two strains. The levels of cytokines were significantly higher in the ChoP(-) strain group than in the ChoP(+) strain group in MEWs, but these cytokine levels were low in NWs. The CRP concentration in the ChoP(-) group was high on day 7 in the MEWs. In NWs, the CRP concentration was low in all groups during the experiment.Conclusion: ChoP expression of NTHi changes the organism susceptible to killing by CRP, and the ChoP(+) strain might be gradually eradicated from the middle ear via the CRP-complement cascade, but not from nasopharynx. Based on our findings, phase variation by altering Phosphorylcholine expression of nontypeable Haemophilus influenzae affects bacteria clearance and mucosal immune response in the middle ear and nasopharynx. (c) 2020 Oto-Rhino-Laryngological Society of Japan Inc. Published by Elsevier B.V. All rights reserved.