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目的观察活的/热致死发酵乳杆菌对牛乳β-乳球蛋白(BLG)致敏小鼠Th1/Th2细胞平衡、血清抗体水平及T淋巴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、活的与热致死发酵乳杆菌组。采用ELISA法测定各组小鼠血清总IgE和BLG特异性IgE含量。体外分离培养各组小鼠脾淋巴细胞,采用ELISA法检测细胞上清液中Thl型细胞因子(IL-12、IFN-γ)和Th2型细胞因子(IL-4)的水平,采用流式细胞术检测脾淋巴细胞中CD3+、CD4+和CD8+的百分含量。结果与致敏组相比,活的/热致死发酵乳杆菌组小鼠的IFN-γ/IL-4比值(代表Thl/Th2细胞平衡)显著增高(P<0.05);血清总IgE和BLG特异性IgE水平显著降低(P<0.05);脾淋巴细胞中的CD4+细胞比例升高,CD4+/CD8+比值得到优化。特别是热致死的发酵乳杆菌组抑制IL-4分泌的效果显著优于活菌组(P>0.05),且该组的抗体水平和CD4+/CD8+比值与空白组相比无差异(P>0.05)。结论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Thl占优势的Thl/Th2细胞平衡,阻断IgE分泌及平衡T淋巴细胞亚群数量相关。
Objective To investigate the effect of Lactobacillus fermentum on the balance of Th1 / Th2 cells, the level of serum antibody and the number of T lymphocyte subsets in the milk-induced β-lactoglobulin (BLG) -induced mice, and to explore its effect on alleviating the allergic reaction . Methods Balb / c mice were sensitized by intraperitoneal injection of a mixture of milk BLG and Freund’s adjuvant to establish an animal model of allergy. The experimental animals were randomly divided into blank group, sensitized group, live and heat-killed Lactobacillus group. Serum total IgE and BLG-specific IgE levels were determined by ELISA. Splenic lymphocytes were isolated and cultured in vitro. The levels of Thl type cytokines (IL-12, IFN-γ) and Th2 type cytokines (IL-4) in the supernatant were detected by ELISA. The percentage of CD3 +, CD4 +, and CD8 + in splenic lymphocytes was measured. Results Compared with the sensitized group, the IFN-γ / IL-4 ratio (representing the balance of Thl / Th2 cells) in live / lethal Lactobacillus fermentum group was significantly increased (P <0.05) (P <0.05). The proportion of CD4 + cells in splenic lymphocytes increased and the ratio of CD4 + / CD8 + was optimized. In particular, the thermophilic Lactobacillus fermentum group was significantly better than the viable bacteria group in inhibiting the secretion of IL-4 (P> 0.05), and there was no difference in antibody level and CD4 + / CD8 + ratio between this group and the blank group (P> 0.05 ). Conclusion Lactobacillus fermentum can improve the symptom of BLG allergy in mice. The effect of Lactobacillus fermentum may be related to Thl / Th2 cell balance, blocking IgE secretion and balancing the number of T lymphocyte subsets.