Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand.
Arch Oral Biol. 2013 Jan;58(1):82-93. doi: 10.1016/j.archoralbio.2012.06.011. Epub 2012 Jul 13.
To examine CD99 expression and its functional role in ICAM-1 induction in human gingival fibroblasts (HGFs) and human gingival epithelial cells (HGECs) by activating cells with anti-CD99 monoclonal antibody, MT99/3.
Engagement of CD99 with agonistic antibodies has been shown to regulate immune responses, cell adhesion and migration, and cell death in several studies. Particularly, this engagement results in transendothelial migration of leukocytes mediated by intercellular adhesion molecule-1 (ICAM-1) induction in endothelial cells.
Total mRNA and protein were isolated from HGFs and HGECs for analyses of CD99 and ICAM-1 expression. Surface expression of CD99 and ICAM-1 was analysed by flow cytometry, and the detection of soluble ICAM-1 was assayed by immunoprecipitation and ELISA.
CD99 surface expression was constitutive on HGFs to a greater extent than that on HGECs. CD99 ligation with MT99/3 induced ICAM-1 mRNA expression in HGFs, but not in HGECs. Interestingly, CD99 ligation led to an increased level of soluble ICAM-1 detected in culture supernatant, whereas interleukin-1β (IL-1β) treatment induced expression of membrane-bound ICAM-1. Furthermore, ICAM-1 induction by CD99 engagement was demonstrated to involve the activation of the p50 subunit of nuclear factor-kappaB (NF-κB), extracellular signal-regulated kinase, and p46 c-Jun N-terminal kinase that differed from that by IL-1β treatment.
Our study has shown the involvement of CD99 ligation in the up-regulation of ICAM-1 expression and its secretion in gingival fibroblasts, which may be essential for better understanding of the pathogenesis of periodontal disease.
通过用抗 CD99 单克隆抗体 MT99/3 激活细胞，研究 CD99 在人牙龈成纤维细胞（HGFs）和人牙龈上皮细胞（HGECs）中诱导细胞间黏附分子-1（ICAM-1）表达中的作用及其功能。
在几项研究中，已经表明与激动性抗体结合的 CD99 可调节免疫反应、细胞黏附和迁移以及细胞死亡。特别是，这种结合导致内皮细胞中细胞间黏附分子-1（ICAM-1）诱导的白细胞跨内皮迁移。
从 HGFs 和 HGECs 中分离总 mRNA 和蛋白质，用于分析 CD99 和 ICAM-1 的表达。通过流式细胞术分析 CD99 和 ICAM-1 的表面表达，通过免疫沉淀和 ELISA 检测可溶性 ICAM-1 的检测。
CD99 表面表达在 HGFs 中比在 HGECs 中更为显著。MT99/3 与 CD99 的结合诱导 HGFs 中 ICAM-1 mRNA 的表达，但在 HGECs 中则不然。有趣的是，CD99 结合导致培养上清液中可检测到可溶性 ICAM-1 水平增加，而白细胞介素-1β（IL-1β）处理则诱导膜结合 ICAM-1 的表达。此外，CD99 结合诱导的 ICAM-1 表达涉及核因子-κB（NF-κB）p50 亚基、细胞外信号调节激酶和 p46 c-Jun N-末端激酶的激活，这与 IL-1β 处理不同。
本研究表明 CD99 结合参与了牙龈成纤维细胞中 ICAM-1 表达的上调及其分泌，这可能对于更好地理解牙周病的发病机制至关重要。
