The Effects Of Peptidoglycan From Lactobacillus On Improving Allergy Responses Via TLR2/NF-κB Pathway Inβ-Lactoglobulin-Sensitized Mice

New data showed that whole peptidoglycan (WPG), as a critical component of cell wall from Lactobacillus acidopHilus(L.acidophilus), was possibly correlated with the immunomodulatory effects of probiotics via Toll-like receptor (TLR)2/NF-kappaB (NF-κB) signaling pathway. However, it is unclear whether the anti-allergy ability of L.acidophilus was attributed to TLR2/NF-KB pathway. Therefore, WPG from L.acidophilus with significantly inhibited function on β-Lg allergy was prepared as the research object. Screening platform for cell immunity was established at first, the effects of the different doses of WPG from L.acidophilus on the lymphocyte proliferation, antibody and cytokines production, CD4+/CD8+ratio, cytokine and gene expression of T-helper (Th)1/Th2and regulatory T cells (Treg)/Th17balance were observed; Animal models were further established using β-Lg as allergy. We administered allergic mice with varying doses of WPG to observe the effects of TLR2/NF-κB signaling pathway on the development of allergy, and investigate the correlations between TLR2/NF-κB and Treg/Th17imbalance. The results may reflect a new protective mechanism of the Lactobacilli to limit excessive inflammation and collateral tissue damage during allergy, and provid theoretical basises for screening and usage of anti-allergic Lactobacillus.The first experiment:Cell culture experiment.1. To observe the effects of different dose of WPG from Lactobacillus on the lymphocyte proliferation in vitro. WPG could both accelerate proliferation of splenocytes directly and show a dose-dependent relationship (P<0.05).2. Effect of different Lactobacillus on splenic subtype, Th1/Th2and Treg/Th17balance, and antibody production of allergic splenic lymphocyte in mice in vitro. Compared with the allergy group, the secretion of total IgE and β-Lg-specific IgE were decreased in the splenocytes stimulated with WPG in a dose manner; In addition, the numbers of CD3+and CD4+cells were significantly promoted by WPG, as well as and the ratio of CD4+/CD+cells in order to maintain the balance of T lymphocyte subsets; WPG administration significantly enhanced the gene ratio of T-bet/GATA-3and Foxp3/RORyt to regulate Th1/Th2and Treg/Th17balance, especially in medium and high dose group.The second experiment:Animal experiment.To analyze the effects of different dose of WPG from Lactobacillus on the imbalance of Treg/Th17and TLR2/NF-κB signaling pathway.The results indicated that intraperitoneal injection of medium and high dose of WPG had an ability to effectively inhibit IgE-induced β-Lg allergy compared with allergy group (P<0.05); Meanwhile, treatment with different doses of WPG increased the levels of Treg-type cytokine and transcription factor (TGF-P, Foxp3, CD25), but decreased those of Th17(IL-17, RORyt) and inflammatory cytokines (IL-6, IL-23) in medium and high dose group to improved the Th17/Treg balance. Furthermore, compared with allergy group, TLR2/NF-κB signialling were clearly activated in spleen of WPG group in a dose manner, especially positive correlated with the Foxp3expression, but negative correlated with the RORyt expression in WPG-treated group (P<0.05).On this study, WPG form L.acidophilus have the effects on release β-Lg allergy, which may attribute to TLR2/NF-κB signaling pathway, leading to the balance of splenic subtypes, Thl/Th2and Treg/Th17cell balance.