目的 通过户尘螨(Dermatophagoides pteronyssinus)2类变应原Der p 2 T细胞表位融合肽对哮喘小鼠的特异性免疫治疗,探讨信号转导因子和转录活化因子6(signal transducer and activator of transcription factor 6, STAT6)的变化及其特异性免疫治疗的作用机制。 方法 30只小鼠用随机数表法分为哮喘组、Der p 2 T细胞表位融合肽免疫治疗组(简称免疫治疗组)和阴性对照组(PBS组),每组10只。哮喘组和免疫治疗组分别于第0、7、14天经小鼠腹腔注射100 μl致敏液[含100 μg/ml Der p2和2% Al(OH)3的PBS液],PBS组注射等量PBS液[含2% Al(OH)3]。哮喘组和免疫治疗组自第21天起,雾化吸入0.5 μg/ml Der p 2致敏液,1次/d × 30 min,连续7 d; PBS组雾化吸入等量PBS液。免疫治疗组在第25~27天雾化前30 min,经腹腔注射100 μg/ml Der p 2 T细胞表位融合肽200 μl, PBS组和哮喘组注射等量PBS液。末次雾化吸入24 h后处死小鼠,收集每组小鼠的支气管肺泡灌洗液(BALF),用ELISA检测BALF中白细胞介素-4(IL-4)、IL-13、γ干扰素(IFN-γ)水平。取肺组织提取肺组织全蛋白,蛋白质印记(Western blotting)检测肺组织全蛋白中STAT6和磷酸化STAT6(p-STAT6)的表达情况。组间样本的均数比较采用单因素方差分析。 结果 免疫治疗组小鼠的IFN-γ水平为(234.40 ± 24.46)pg/ml,高于哮喘组的(155.80 ± 20.53)pg/ml(P 〈 0.01);免疫治疗组小鼠的IL-4和IL-13水平分别为(30.00 ± 5.50)和(174.50 ± 25.99)pg/ml,均低于哮喘组小鼠的(53.28 ± 8.26)和(308.10 ± 28.32)pg/ml(P 〈 0.01)。免疫治疗组小鼠STAT6、p-STAT6的相对表达量分别为0.803 ± 0.221和0.966 ± 0.323,均低于哮喘组的1.669 ± 0.296和1.735 ± 0.298(P 〈 0.01)。 结论 Der p 2 T细胞表位融合肽可能通过抑制STAT6治疗哮喘组小鼠。
Objective To investigate the alterations of signal transducer and activator of transcription factor 6(STAT6) signaling in a mouse model of asthma receiving treatment with Dermatophagoides pteronyssinus group 2 allergen(Der p 2) T cell fusion epitope and the mechanisms of the specific immunotherapy. Methods Thirty mice were randomly divided into three groups by the random number table method: the asthma group, the treatment group receiving immunotherapy with Der p 2 T cell fusion epitope, and the negative control group (PBS group)(n = 10 in each group). Mice in the asthma and the treatment groups received intraperitoneal (i. p.) injection of 100 μl Der p 2 solution [PBS containing 100 μg/ml Der p 2 and 2% Al(OH)3] on days 0,7 and 14, respetively, while mice in the PBS group received same volume of PBS containing 2% Al(OH)3. From day 21, 30-min steam inhalation of 0.5 μg/ml Der p 2 was applied to the asthma and treatment groups (once daily for 7 successive days), and the PBS group inhaled same volume of PBS. From day 25 to day 27, the mice in the treatment group received i. p. injection of 200 μl of Der p 2 T cell fusion epitope (100 μg/ml) while the PBS and the asthma groups received the same volume of PBS. Mice were sacrificed at 24 h after the last inhalation, the bronchoalveolar lavage fluid (BALF) collected, and the total protein was extracted from the lung tissue. The levels of IFN-γ, IL-4 and IL-13 in BALF were determined by ELISA. The expression of STAT6 and phosphorylated STAT6 (p-STAT6) in the lung tissue was detected by Western blotting. Data were analyzed with the one-way variance analysis (ANOVA) method. Results The level of IFN-γ in the treatment group[(234.40 ± 24.46) pg/ml] was significantly higher than that in the asthma group[(155.80 ± 20.53) pg/ml](P 〈 0.01). The levels of IL-4 and IL-13 in the treatment group [(30.00 ± 5.50) pg/ml and (174.50 ± 25.99) pg/ml, respectively] were both significantly lower than those i