Regulation of oral mucosal immunity in human oral epithelial cells and periodontitis

1.口腔上皮细胞在细胞内组成型表达白细胞介素18（IL-18）的前体形式。干扰素-γ (IFN-γ) 引发后，细胞与中性粒细胞丝氨酸蛋白酶、蛋白酶 3 (PR3) 和脂多糖 (LPS) 共刺激，产生具有生物活性的 IL-18。研究发现 PR3 通过 G 蛋白偶联蛋白酶激活受体 2.2 激活口腔上皮细胞。口腔上皮细胞不表达细菌模式识别受体 CD 14，但表达 Toll 样受体 (TLR)/MD-2/MyD88 系统，这在先天免疫识别中至关重要。然而，即使在可溶性 CD14 存在的情况下，细胞也难以抵抗细菌成分。细胞能够对黑色素细菌 (BPB) 的成分做出反应。用 IFN-γ 启动后，细胞获得了对许多细菌成分的反应性。3。 BPB 中的非内毒性糖蛋白以 CD14 和 TLR2 依赖性方式激活宿主细胞。 4．表达CD14的人牙龈成纤维细胞（HGF）与口腔上皮细胞具有相同的特性。人牙周膜成纤维细胞 (HPLF) 表达 TLR2 的能力强于 HGF。 HGF主要响应革兰氏阴性菌成分，HPLF主要响应革兰氏阳性菌成分。来自牙周病细菌的半胱氨酸蛋白酶（牙龈蛋白酶）可降解 HGF 上的 CD14，从而抑制对细菌成分的 CD14 依赖性反应。5．人类唾液腺组成型表达 CD14 并以可溶形式分泌到唾液中。

1. Oral epithelial cells constitutively express precursor form of interleukin-18 (IL-18) in the cells. Bioactive IL-18 was produced from the cells on costimulation with neutrophil serine proteinase, proteinase 3 (PR3), and Iipopolysaccharide (LPS) after interferon-γ (IFN-γ)-priming. PR3 was found to activate oral epithelial cells through G protein-coupled protease-activated receptor-2.2. Oral epithelial cells do not express a bacterial pattern recognition receptor, CD 14, and express Toll-like receptors (TLRs)/MD-2/MyD88 system, which is critical in innate immune recognition. However, the cells are refractory to bacterial components even in the presence of soluble CD14, The cells are able to respond to components from black-pigmented bacteria (BPB). The cells acquire responsiveness to many bacterial components after priming with IFN-γ.3. Nonendotoxic glycoprotein from BPB activates host cells in a CD14- and TLR2-dependent manner.4. CD14-expreswsing human gingival fibroblasts (HGF) have the same property with oral epithelial cells. Human periodontal ligament fibroblasts (HPLF) express TLR2 more strongly than HGF. HGF mainly respond to Gram-negative, and HPLF mainly respond to Gram-positive bacterial components, respectively. Cysteine proteinases (gingipains) from periodontopafhic bacteria degrade CD14 on HGF, consequently, suppress CD14-dependent responsiveness to bacterial components.5. Human salivary glands constitutively express CD14 and secrete as a soluble form in saliva.