乳酸菌表面蛋白在与宿主相互作用中发挥了重要作用，但其免疫调节功能及效应分子尚不明确。Toll样受体2（TLR2）与蛋白类配体的免疫识别被认为是介导宿主免疫应答的主要途径。本项目以3株不同免疫调节特性的乳酸菌为研究对象，应用分子交联、免疫印迹以及质谱分析技术从乳酸菌表面蛋白中筛选和鉴定树突状细胞TLR2结合蛋白（TLR-P），通过重组表达、单抗制备以及免疫亲和层析等技术手段分离纯化天然结构的TLR-P，并对脂质化修饰基团及位点进行分析，探明TLR-P分子结构特征。应用人源树突状细胞建立体外免疫刺激模型，研究不同乳酸菌TLR-P诱导树突状细胞的表面共刺激分子、细胞因子以及胞内信号转导分子的表达水平，探讨TLR-P对树突状细胞的免疫激活效应及作用规律，阐明TLR-P结构特征与免疫调节效应之间的关系，为乳酸菌免疫调节剂的高效筛选以及新型功能乳制品开发提供理论依据

Surface proteins of lactic acid bacteria play an important role in their interactions with host cells. However, the immunomodulatory factors in surface proteins and their action mechanisms are not clear.The immune recognition ligand by Toll-like receptor 2 (TLR2) is considered to be the main way to activate the host immune system. In this project, three lactobacillus strains which showed different immunomodulatory characteristics in our previous works, will be used for isolation and identification of dendritic cell Toll-like receptor 2 (TLR2) -interacting protein (TLR-P) from surface protein using molecular cross-linking, Western-blotting and mass spectrometry. The natural TLR-Ps obtained by recombinant expression, monoclonal antibody preparation and immunoaffinity chromatography techniques will be analyzed for their structure and modification site of the lipidated group to elucidate the molecular structural features. The in vitro immune stimulation model using human-derived dendritic cells will be established to study expression level of costimulatory molecules, cytokines and intracellular signaling molecules of dendritic cells induced by TLR-P from different strains, these results will reveal the roles of TLR-P in immune activation and moderation of dendritic cell, and clarify the relationship between the TLR-P structural characteristics and immunomodulatory effects. The findings of this project will have important theoretical and practical significance for efficient screening of lactobacillus immunomodulators and developing new type of probiotic functional dairy.