干酪乳杆菌干预对花生过敏小鼠模型的免疫调节作用

Immunomodulatory effects of Lactobacillus casei on a murine model of peanut allergy

【目的】研究干酪乳杆菌(Lactobacillus casei)Zhang在预防及治疗花生过敏方面的作用。【方法】构建小鼠花生过敏模型,饲喂L.casei Zhang,并检测血清中IgE、IgG1和IgG2a抗体,粪便中组胺和IgA抗体,细胞因子和CD4+Foxp3+Tregs细胞的含量。【结果】与模型组相比,口服L.casei Zhang的实验组小鼠血清过敏原特异性的IgG2a和粪便总IgA抗体水平有所上调,花生过敏症状及Th2型反应(血清总IgE、特异性IgE、粪便组胺和IL-4水平等指标)明显降低。L.casei Zhang的摄入对血清IgG1抗体和其他细胞因子(IL-10、IL-12及IFN-γ)的表达水平没有明显影响,而IFN-γ/IL-4的比例及实验组脾脏和肠系膜淋巴结中CD4^+Foxp3^+Tregs细胞的表达增加。【结论】L.casei Zhang能促使Th2优势反应向Th1方向转变,从而起到预防和治疗花生过敏的作用。

[Objective] We studied the immunomodulatory potential ofLactobacillus casei Zhang on preventive and therapeutic effects. [Methods] A murine model of peanut allergy was established and fed with L. casei Zhang. Then we measured the levels of IgE, IgG1 and IgG2a antibodies in blood serum, histamine and IgA antibody in feces, and cytokines and CD4^＋Foxp3^＋ Tregs cells. [Results] Intragastric administration with L. casei Zhang, prior or after allergic sensitization, increased levels of serum allergen-specific IgG2a and fecal total IgA antibodies. Additionally, systemic anaphylactic symptoms and Th2 responses such as total and specific IgE antibodies, histamine release and IL-4 production were decreased. In contrary, L. casei Zhang had no obvious influence on the serum IgG1 antibody and other cytokines （IL-10, IL-12 and IFN-y）. Successful immunomodulation by pre- and post-treatment were further demonstrated by the increase of IFN-y/IL-4 ratio in vitro and enrichment of CD4^＋Foxp^3＋ Tregs in spleen and mesenterie lymph nodes. [Conclusion] L. casei Zhang could shift the Th2 dominant response to a Thl response, which finally play a role in preventing and treating peanut allergy.