CD99 ligation induces intercellular cell adhesion molecule-1 expression and secretion in human gingival fibroblasts.
OBJECTIVE
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.


BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand.
Suttichai
S
Krisanaprakornkit
Pareena
P
Chotjumlong
Supansa
S
Pata
Nuttapol
N
Chruewkamlow
Vichai
V
Reutrakul
Watchara
W
Kasinrerk
D000071443:12E7 Antigen; D000873:Anthracenes / Q000494:pharmacology; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000494:pharmacology*; D002070:Butadienes / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000494:pharmacology*; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D042783:Endothelial Cells / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D005881:Gingiva / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D018799:Intercellular Adhesion Molecule-1 / Q000187:drug effects*; D053583:Interleukin-1beta / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects; D019169:Jurkat Cells; D007962:Leukocytes / Q000187:drug effects; D007976:Leupeptins / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D052002:NF-kappa B p50 Subunit / Q000187:drug effects; D009570:Nitriles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
D000071443:12E7 Antigen; D000873:Anthracenes; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D002070:Butadienes; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D007093:Imidazoles; D053583:Interleukin-1beta; D007976:Leupeptins; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D009570:Nitriles; D011725:Pyridines; C113580:U 0126; D018799:Intercellular Adhesion Molecule-1; C432165:pyrazolanthrone; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde