Komine Ken-Ichi, Kuroishi Toshinobu, Ozawa Akiko, Komine Yumiko, Minami Takumi, Shimauchi Hidetoshi, Sugawara Shunji
Division of Oral Immunology, Department of Oral Biology, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
Mol Immunol. 2007 Mar;44(7):1498-508. doi: 10.1016/j.molimm.2006.09.003. Epub 2006 Oct 9.
Lactoferrin (Lf) is a member of the transferrin family of iron-binding anti-bacterial proteins, present in most exocrine secretions, such as saliva, and plays an important role in mucosal defense. In this study, we identified small Lf peptides with Con A low-affinity in the parotid saliva of chronic periodontitis patients by Con A two-dimensional immunoelectrophoresis, Con A affinity chromatography and Western blotting using anti-human Lf polyclonal Ab. N-terminal amino acid sequencing of the four Con A low-affinity Lf peptides confirmed them to be fragments of intact Lf. The detection ratio of the proteinase 3 (PR3)-like activity was elevated in the parotid saliva of periodontitis patients and was associated with the severity of clinical symptoms. PR3 protein was also detected in the parotid saliva of periodontitis patients, and PR3, but not human leukocyte elastase and cathepsin G, degraded intact Lf. Con A low-affinity saliva Lf peptides showed no anti-bacterial activity against Escherichia coli, and had a reduced iron-chelating capacity. Con A low-affinity saliva Lf peptides, PR3-treated Lf preparation and two of four synthetic polypeptides induced the production of interleukin IL-6, monocyte chemoattractant protein-1 and IL-8, and the activation of NF-kappaB in human oral epithelial HSC-2 cells. Furthermore, concentrations of the Lf peptides in the parotid saliva of periodontitis patients were increased with a correlation to the severity of clinical symptoms. These results suggest that Lf in the parotid saliva of periodontitis patients was degraded into small peptides by the PR3-like activity with the capability to induce inflammatory mediators.
乳铁蛋白（Lf）是转铁蛋白家族中一种结合铁的抗菌蛋白，存在于大多数外分泌液中，如唾液，并在黏膜防御中发挥重要作用。在本研究中，我们通过伴刀豆球蛋白A二维免疫电泳、伴刀豆球蛋白A亲和层析以及使用抗人Lf多克隆抗体的蛋白质印迹法，在慢性牙周炎患者的腮腺唾液中鉴定出了伴刀豆球蛋白A低亲和力的小Lf肽段。对这四个伴刀豆球蛋白A低亲和力Lf肽段进行N端氨基酸测序，证实它们是完整Lf的片段。蛋白酶3（PR3）样活性在牙周炎患者腮腺唾液中的检测率升高，且与临床症状的严重程度相关。在牙周炎患者的腮腺唾液中也检测到了PR3蛋白，并且PR3能降解完整的Lf，而人白细胞弹性蛋白酶和组织蛋白酶G则不能。伴刀豆球蛋白A低亲和力唾液Lf肽段对大肠杆菌无抗菌活性，且铁螯合能力降低。伴刀豆球蛋白A低亲和力唾液Lf肽段、PR3处理的Lf制剂以及四个合成多肽中的两个，可诱导人口腔上皮HSC - 2细胞产生白细胞介素IL - 6、单核细胞趋化蛋白 - 1和IL - 8，并激活核因子κB。此外，牙周炎患者腮腺唾液中Lf肽段的浓度升高，且与临床症状的严重程度相关。这些结果表明，牙周炎患者腮腺唾液中的Lf通过PR3样活性被降解为小肽段，这些小肽段具有诱导炎症介质的能力。
