Duez Catherine, Dakhama Azzeddine, Tomkinson Adrian, Marquillies Philippe, Balhorn Annette, Tonnel André-Bernard, Bratton Donna L, Gelfand Erwin W
Department of Pediatrics, Division of Basic Sciences, National Jewish Medical and Research Center, Denver, CO 80206, USA.
J Allergy Clin Immunol. 2004 Oct;114(4):820-5. doi: 10.1016/j.jaci.2004.08.011.
Eosinophils play a major role in allergic airway inflammation because of their ability to release toxic mediators. In addition, they are able to migrate toward draining thoracic lymph nodes (TLNs) after intratracheal administration, where they can function as antigen-presenting cells.
In this study, we evaluated in vivo eosinophil migration toward the TLN after allergen sensitization and analyzed expression of molecules involved in antigen presentation.
Mice were sensitized by intraperitoneal injection of ovalbumin on days 1 and 10 and challenged once intranasally with ovalbumin on day 20. The kinetics of eosinophilia was evaluated in blood, lung tissue homogenate, bronchoalveolar lavage fluid, and TLN. Cell surface staining was analyzed by flow cytometry.
The kinetics of eosinophil recruitment was similar in TLN, lung tissue, and blood, beginning at 12 hours and peaking at 48 hours after allergen challenge. Approximately 70% of TLN eosinophils expressed MHC class II molecules, compared with less than 25% in blood and lungs. Moreover, TLN eosinophils expressed higher levels of MHC class II and CD86 compared with blood and lung eosinophils. Most eosinophils expressed CD80 and CD54, whereas only a few eosinophils expressed CD40. Eosinophils in lungs and TLN appeared to be activated with lower CD62-ligand expression compared with blood eosinophils.
The presence of eosinophils with a different phenotype in the TLN at early time points after allergen challenge of sensitized mice supports their capacity to serve as antigen-presenting cells, sustaining allergic/inflammatory responses in the airways.
嗜酸性粒细胞因其释放毒性介质的能力，在过敏性气道炎症中起主要作用。此外，气管内给药后，它们能够迁移至引流的胸段淋巴结（TLN），在那里它们可以作为抗原呈递细胞发挥作用。
在本研究中，我们评估了变应原致敏后嗜酸性粒细胞在体内向TLN的迁移情况，并分析了参与抗原呈递的分子的表达。
在第1天和第10天通过腹腔注射卵清蛋白使小鼠致敏，并在第20天经鼻用卵清蛋白攻击一次。在血液、肺组织匀浆、支气管肺泡灌洗液和TLN中评估嗜酸性粒细胞增多的动力学。通过流式细胞术分析细胞表面染色情况。
嗜酸性粒细胞募集的动力学在TLN、肺组织和血液中相似，在变应原攻击后12小时开始，48小时达到峰值。约70%的TLN嗜酸性粒细胞表达MHC II类分子，而血液和肺中的这一比例不到25%。此外，与血液和肺嗜酸性粒细胞相比，TLN嗜酸性粒细胞表达更高水平的MHC II类分子和CD86。大多数嗜酸性粒细胞表达CD80和CD54，而只有少数嗜酸性粒细胞表达CD40。与血液嗜酸性粒细胞相比，肺和TLN中的嗜酸性粒细胞似乎以较低的CD62配体表达被激活。
致敏小鼠变应原攻击后早期时间点，TLN中存在具有不同表型的嗜酸性粒细胞，这支持了它们作为抗原呈递细胞的能力，维持气道中的过敏性/炎症反应。
