中文摘要：

目的：观察热致死的发酵乳杆菌对牛乳β-乳球蛋白（BLG）致敏小鼠Th1/Th2细胞平衡、血清抗体水平及T细胞亚群数量的影响,探讨其缓解过敏反应的作用。方法：用牛乳BLG和弗氏佐剂的混合液腹腔注射诱发BALB/c小鼠致敏,建立动物过敏模型。将实验动物随机分为空白组、致敏组和不同剂量的热致死发酵乳杆菌组。采用ELISA法测定各组小鼠血清总IgE、BLG特异性IgE和总IgG含量。体外分离培养各组小鼠脾细胞,采用ELISA法检测细胞上清液中Th1型细胞因子（IL-12、IFN-γ）和Th2型细胞因子（IL-4）水平,采用流式细胞术检测脾淋巴细胞中CD3＋、CD4＋和CD8＋T百分含量。结果：发酵乳杆菌组小鼠脾细胞培养上清液中IFN-γ/IL-4比值为13.53,显著高于致敏组的3.34（P〈0.05）;血清总IgE、BLG特异性IgE和总IgG水平显著降低（P〈0.05）;脾细胞中CD3＋和CD4＋T细胞比例升高,CD4＋/CD8＋比值趋近正常组。特别是高剂量的热致死发酵乳杆菌组小鼠脾细胞培养上清液中抑制IL-4分泌的效果显著优于致敏组（P〉0.05）,且该组小鼠血清的抗体水平和CD4＋/CD8＋比值与空白组相比无差异（P〉0.05）。结论：热致死的发酵乳杆菌干预可改善小鼠的BLG过敏症状,其作用可能与促进Th1占优势的Th1/Th2细胞平衡,阻断IgE、IgG分泌及平衡T细胞亚群数量相关。

英文摘要：

Objective：Effects of dead Lactobacillus fermentum on the Thl/Th2 cell balance, antibody production and T lymphocyte subsets of milk BLG-sensitized mice were investigated. Methods：The rats were intraperitoneally injected with the mixture of milk BLG and Freund＇s adjuvant, and the food allergic experimental rat model was made. The rats were randomly divided into 4 groups：blank group,fo0d allergy group and heat-kilted Lactobacillus fermentum group. The total IgE, BLG-specific IgE and total IgG contents in the serum of sensitized rats were measured with ELISA;Splenic lymphocytes were isolated and cultured in vitro,the levels of Thl type cytokine （IL-12,IFN-γ） and Th2 type cytokine （IL-4） were detected by ELISA;the lymphocyte subgroups in the spleen were analyzed by flow cytometry. Results：The IFN-γ/IL-4 value which represents the Thl/Th2 cell balance both increased significantly in L. fermentum group compared with those of allergy group （ P 〈 0.05 ）, but the serum levels of total and BLG-IgE, total IgG decreased significantly （ P 〈 0.05 ）. In addition, the percentage of CD3＋ , CD4＋ T cell was increased and the ratio of CD4＋ to CD8 ＋ T cells of the mice were optimized. Investigated the production of IL-4 from high level Lactobacillus fermentum administered mice was significantly lower as com- pared to allergy group, at the same time, its antibody production and CIM ＋/ CD8 ＋ ratio were no difference compared with the blank group（ P 〉 O. 05 ）. Conclusion： Intragastric administration of inactivated L. fermentum may be effective in preventing and alleviating BLG allergic symptoms by the improvement of the Thl/Th2 cell balance toward Thl dominance,the inhibition of IgE and IgG oroduction and modulating splenic Tlymphocyte subsets.