Supplementary Material for: Birch Pollen Immunotherapy in Mice: Inhibition of Th2 Inflammation Is Not Sufficient to Decrease Airway Hyper-Reactivity

<b><i>Background:</i></b> Suppression of Th2 cytokine production by allergen-specific Th2 cells is considered to be critical for the suppression of allergic symptoms by subcutaneous immunotherapy. The aim of this study was to develop a mouse model for birch pollen (BP) immunotherapy to elucidate the underlying mechanisms that contribute to the improvement of clinical symptoms. <b><i>Methods:</i></b> Mice with BP-induced allergic airway inflammation received weekly subcutaneous immunotherapy (SCIT) injections with BP extract (BPE) adsorbed to alum. The effect of an increasing dose of BPE adsorbed to a fixed concentration of alum on the suppression of airway inflammation and airway hyper-responsiveness (AHR) was determined. After 2, 4, 6 or 8 immunotherapy injections, the mice were rechallenged with the same allergen and all hallmarks of allergic asthma were evaluated. <b><i>Results:</i></b> Suppression of the immunological parameters by immunotherapy was dependent on the BPE dose. Two injections were sufficient to suppress IL-4, IL-5, IL-13, IL-10 and IFN-G production, eosinophil recruitment and peribronchial inflammatory infiltrates. BP-specific immunoglobulins were upregulated, but this was not sufficient to reduce AHR. Eight injections were needed to suppress AHR. The gradual reduction in AHR was inversely associated with the increase of BP IgG2a. <b><i>Conclusions:</i></b> BP SCIT induces an early suppression of Th2-mediated eosinophilic airway inflammation, but AHR is only effectively reduced after continued SCIT conceivably by allowing IgG2a antibody titres to build up. i 2014 S. Karger AG, Basel

<b><i>背景：</i></b> 过敏原特异性Th2细胞对Th2细胞因子生成的抑制作用，被认为是皮下免疫疗法（subcutaneous immunotherapy, SCIT）缓解过敏症状的核心机制。本研究旨在构建桦树花粉（birch pollen, BP）免疫疗法的小鼠模型，以阐明可改善临床症状的潜在作用机制。<b><i>方法：</i></b> 针对桦树花粉诱导的过敏性气道炎症小鼠，每周给予吸附于明矾（alum）的桦树花粉提取物（birch pollen extract, BPE）进行皮下免疫疗法注射。本研究考察了固定浓度明矾吸附的BPE剂量递增，对气道炎症与气道高反应性（airway hyper-responsiveness, AHR）抑制效果的影响。在完成2、4、6或8次免疫疗法注射后，用相同过敏原对小鼠进行再次激发，并评估过敏性哮喘的所有标志性病理特征。<b><i>结果：</i></b> 免疫疗法对免疫学指标的抑制效果依赖于BPE剂量。仅2次注射即可抑制IL-4、IL-5、IL-13、IL-10及IFN-γ的生成，减少嗜酸性粒细胞募集与支气管周围炎性浸润。桦树花粉特异性免疫球蛋白水平上调，但该变化不足以改善气道高反应性。需8次注射方可抑制气道高反应性，其逐步降低与桦树花粉IgG2a水平升高呈负相关。<b><i>结论：</i></b> 桦树花粉皮下免疫疗法可早期抑制Th2介导的嗜酸性粒细胞性气道炎症，但气道高反应性仅在持续接受免疫疗法后才可得到有效改善，推测其机制为IgG2a抗体滴度得以逐步积累。© 2014 S. Karger AG，巴塞尔