Lactobacilli have beneficial effects on the digestive and immune systems. Surface layer protein SlpA is a key factor in probiotic–host crosstalk; however, how this immunomodulation affected by Lactobacillus SlpA is not yet well understood. In a LPS-induced RAW 264.7 cell model, SlpA derived from Lactobacillus acidophilus CICC 6074 significantly reduced the inflammatory responses as evidenced by inhibition of the production of inflammatory mediators such as iNOS and COX-2 and inflammatory cytokines, including TNF-α, IL-10, IL-1β, IFN-α and IFN-β, which may associate with TLR4-dependent MAPK and NF-κB as well as intracellular NOD2- and NLRP3-related signaling inactivation. Most importantly, SlpA ameliorates DSS-induced mice colitis indicated by reduced colitis symptoms including body weight loss, colonic atrophy and colonic mucosal damage, which may owe to a decrease in inflammatory cytokines. These findings suggest that SlpA has an ameliorative effect on the inflammation response and therefore a potential therapeutic role in treating colitis.

乳酸杆菌对消化和免疫系统具有有益作用。表面层蛋白SlpA是益生菌与宿主之间串扰的关键因素。然而，这种免疫调节如何受乳杆菌SlpA影响尚不清楚。在LPS诱导的RAW 264.7细胞模型中，源自嗜酸乳杆菌的SlpA如抑制iNOS和COX-2等炎性介质以及包括TNF-α，IL-10，IL-1β，IFN-α和IFN-β在内的炎性细胞因子的产生，CICC 6074可显着降低炎性反应。可能与TLR4依赖性MAPK和NF-κB以及细胞内NOD2和NLRP3相关的信号失活有关。最重要的是，SlpA改善了DSS诱导的小鼠结肠炎，其表现为结肠炎症状减轻，包括体重减轻，结肠萎缩和结肠粘膜损伤，这可能是由于炎性细胞因子的减少所致。这些发现表明，SlpA对炎症反应具有改善作用，因此在治疗结肠炎中具有潜在的治疗作用。