婴儿双歧杆菌对花生过敏小鼠模型肠道Th2反应的调节

Bifidobacterium infantis inhibits peanut-specific intestinal Th2 response

目的研究婴儿型双歧杆菌对花生过敏小鼠肠道Th2型反应的调节作用。方法通过应用花生蛋白诱导肠道的Th2型反应,建立食物过敏小鼠模型。过敏小鼠灌胃给予婴儿型双歧杆菌(ATCC菌或CGMCC0313-2)或不做处理。然后分离小鼠小肠黏膜CD4+T细胞或DC,另取肠黏膜组织进行石蜡包埋甲苯胺蓝染色肥大细胞计数,HE染色进行嗜酸细胞和单个核细胞计数,流式细胞检测CD4+T中Th2(CD4+IL-4+T)细胞和Treg(CD4+CD25+Foxp3+T)比例,另取CD4+T进行CFSE标记,与DC共培养4 d后流式细胞检测CD4+T增殖反应,收集细胞培养液ELISA检测IL-4、IL-5和IL-13分泌水平。结果过敏组小鼠Th2型细胞数,CD4+T细胞增殖反应,IL-4、IL-5和IL-13水平,肠黏膜中肥大细胞、嗜酸性细胞和单个核细胞数均明显高于对照组(P<0.01),而Treg数目低于对照组(P<0.01),婴儿双歧杆菌干预后,婴儿双歧杆菌组Th2型细胞数,IL-4、IL-5和IL-13水平,肠黏膜中肥大细胞、嗜酸性细胞和单个核细胞数均明显低于过敏组(P<0.01),而Treg数目高于过敏组(P<0.01)。结论口服婴儿型双歧杆菌可以抑制花生过敏导致的肠道Th2型反应。

Objective To study the effects of Bifidobacterium infantis in regulating peanut-specific intestinal Th2 response. Methods Food allergy mice model were established by using peanut allergen to induce intestinal Th2 response. Allergic mice were treated without or with Bifidobacterium infantis （ATCC or CGMCC0313-2） via garage-feeding. CD4＋ T cells or DC were purified from intestine mononuclear cells of mice. Paraffin embedded intestine were stained with toluidine blue to count the mast cells and with HE to count the mononuclear cells and eosinophils. The proportion of Th2 cell （ CD＋ IL-4 ＋ T） and Treg （CD4＋CD25 ＋ Foxp3＋ T） in the CD4＋T cells were determined with flow cytometry. The proliferitive response of CD4 ＋ T cells labeled by CFSE, co-cultured with DC for 4 days, were detected by flow cytometry. The levels of IL-4, IL-5 and IL-13 in supernatant were detected respectively by ELISA. Results The proportion of Th2 cell, the proliferitive response of CD4 ＋ T, the levels of IL4, IL-5 and IL-13, and the counts of mast cells, mononuclear cells and eosinophils were significantly increased in allergic mice compared with controls （ P 〈 0.01 ）, while the proportion of Treg was decreased in allergic mice com- pared with controls （P 〈0. 01 ）. After treatment with Bifidobacterium infantis, the proportion of Th2 cell, the proliferitive response of CD4 ＋ T, the levels of IL-4, IL-5 and IL-13, and the counts of mast cells, mononuclear cells and eosinophils were decreased compared with allergic mice group （ P 〈 0.01 ）. The proportion of Treg was also increased in mice treated with Bifidobacterium infantis compared with allergic mice group （ P 〈 0. 01 ）. Conclusion Oral administration of Bifidobacterium infantis can inhibit peanut allergic Th2 response in the intestine.