Abstract: Objective To investigate the specific immune therapeutic effect of the T cell fusion peptide vaccine from group II allergens from Dermatophagoides pteronyssinus （Der p2）. Methods Thirty mice were randomly divided into three groups， namely a negative control group （a PBS group）， positive control group （an asthma group） and protein Der p2 T cell fusion epitope for specific immunotherapy （SIT） group （a Der p2 T group）. The extract of house dust mites （HDM） was used to establish the asthmatic models in BALB/c mice， and the PBS group was always used with PBS buffer. Thirty minutes before spray inhalation from 25 to 27 days， the mice of the Der p2 T group were respectively injected subcutaneously with the therapeutic proteins for SIT， then the serum and bronchoalveolar lavage fluid （BALF） were collected. ELISA was used to assay the levels of IFN?γ， IL?4， and IL?13 in BALF， as well as serum levels of specific IgE and IgG2a. The lung tissue sections were stained with haematoxylin and eosin （H&E） for pathological examinations. Results The ELISA detection revealed that the number of eosinophil in BALF of the asthmatic mice was （5.57 ± 0.64）×105/ml， which was significantly higher than that in the PBS group ［（0.50 ± 0.30）×105/ml， P < 0.01］， the number of eosinophil in the Der p2 T immunotherapy group decreased significantly ［（3.45 ± 0.36）×105/ml， P < 0.01］. The content of IFN?γ in the PBS group， asthma group and Der p2 T group were （267.00 ± 21.98）， （155.80 ± 20.53） pg/ml and （234.40 ± 24.46） pg/ml respectively. Compared with the asthma group， the mice with Der p2 T vaccine specific immune treatment produced a high level of IFN? γ （P < 0.01）. The content of IL?4 in the PBS group， asthma group and Der p2 T group were （23.40 ± 5.96）， （53.28 ± 8.26） pg/ml and （30.00 ± 5.50） pg/ml respectively. Compared with the asthma group， the content of IL?4 in the mice of the Der p2 T treatment group was significantly lower （P < 0.01）. Compared with the asthma group ［（308.10 ± 28.32） pg/ml］， the content of IL?13 in BALF of the mice in the Der p2 T treatment group was significantly decreased， which was ［（174.50 ± 25.99） pg/ml， P < 0.01］. The content of IL?13 in the PBS group was （95.99 ± 31.14） pg/ml. The lung tissue sections showed that the lung inflammation in the p2 T Der group was significantly less than that in the asthma group， and the inflammatory cell infiltration was significantly decreased， and airway epithelial construction remodeled. Conclusion The Der p2 T cell fusion epitope， which is as vaccines for specific immunotherapy with asthma models， can alleviate effectively allergic inflammation of airway and lung in the mice， and it may be used as a candidate vaccine for asthma.

Key words: Dermatophagoides pteronyssinus； Der p2； T cell epitope； Asthma； Immunotherapy

摘要： 目的 探讨屋尘螨变应原Der p2的4个T细胞表位融合肽对哮喘小鼠的特异性免疫治疗效果。方法 30只雌性BALB/c小鼠随机分为3组，分别为阴性对照组（PBS组）、阳性对照组（哮喘组）以及Der p2 T细胞融合肽治疗组（Der p2 T组）。用屋尘螨粗提取液致敏小鼠建立哮喘模型，PBS组以PBS缓冲液代替，Der p2 T组分别于小鼠致敏第25～27天雾化致敏前30 min行背部皮下注射相应治疗蛋白。最后一次雾化激发24 h后，收集各组小鼠血清及支气管肺泡灌洗液（BALF）。采用ELISA法检测小鼠BALF中IFN?γ、IL?4、IL?13以及血清中屋尘螨粗提取液致敏的特异性IgE、IgG2a抗体水平，并行肺组织切片HE染色。结果 哮喘组小鼠BALF中的嗜酸性粒细胞数量为（5.57 ± 0.64）×105个/ml，高于PBS组［（0.50 ± 0.30）×105个/ml］（P < 0.01）和Der p2 T组 ［（3.45 ± 0.36）×105个/ml］（P < 0.01）。PBS组、哮喘组、Der p2 T组小鼠BALF中IFN?γ含量分别为（267.00 ± 21.98）、（155.80 ± 20.53） pg/ml和（234.40 ± 24.46） pg/ml；与哮喘组比较，Der p2 T组小鼠BALF中产生了较高的IFN?γ水平（P < 0.01）。PBS组、哮喘组、Der p2 T组小鼠BALF中IL?4含量分别为（23.40 ±5.96）、（53.28 ± 8.26） pg/ml和（30.00 ± 5.50） pg/ml；与哮喘组比较，Der p2 T组小鼠BALF中IL?4含量显著降低（P < 0.01）。与哮喘组［（308.10 ± 28.32） pg/ml］比较，Der p2 T组小鼠BALF中IL?13含量［（174.50 ± 25.99） pg/ml］显著下降（P < 0.01）；PBS组鼠BALF中IL?13含量为（95.99 ± 31.14） pg/ml。肺组织切片显示，Der p2 T组小鼠肺部炎症较哮喘组明显减轻，且炎性细胞浸润显著减少、气道上皮结构重塑。结论 Der p2 T细胞表位融合肽可有效改善哮喘小鼠变态反应性气道及肺部炎症，可作为屋尘螨哮喘患者特异性免疫治疗的候选疫苗。

关键词: 屋尘螨；Der p2；T细胞表位；哮喘；免疫治疗