title: The high expression level of programmed death-1 ligand 2 in oral lichen planus and the possible costimulatory effect on human T cells.
abstract: BACKGROUND
  Oral lichen planus (OLP) is a T-cell-mediated chronic autoimmune disease whose precise etiology is unknown. The recently identified costimulatory programmed death-1 (PD-1) molecule and its ligands, PD-L1 and PD-L2, have been identified as CD28-B7 family molecules and constitute a regulatory pathway of potential therapeutic use in immune-mediated diseases.
  
  
  METHODS
  We examined the expression of two ligands of PD-1 at both the protein and gene level in the focal mucosa and peripheral blood of OLP patients using immunohistochemistry and real-time PCR. Next, we used the PD-L2.Ig fusion protein and observed its effects on T cells, which were co-cultured with IFN-γ-treated keratinocytes (KCs) in the presence of PHA.
  
  
  RESULTS
  We found that the expression of PD-L2 at both the gene and protein level was statistically different in peripheral blood and local lesion tissue of patients with OLP compared to the normal controls. The proliferation ability of T cells and the expression level of IFN-γ in the supernatant of the above co-culture model were significantly augmented (P < 0.05). PD-L2.Ig fusion protein significantly aggravated the apoptosis of T cells, inhibited the proliferation of T cells and decreased the release levels of IL-2 and IFN-γ in the model (P < 0.05).
  
  
  CONCLUSIONS
  These data show that the increased expression of PD-L2, as a costimulatory molecule, may have an important modulatory function on the local immune responses of OLP in vivo.
authors: Department of Oral Mucosal Diseases, Ninth People's Hospital Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China.
authors: Guan-Huan
authors: GH
authors: Du
authors: Xiao-Peng
authors: XP
authors: Qin
authors: Qin
authors: Q
authors: Li
authors: Yong-Mei
authors: YM
authors: Zhou
authors: Xue-Min
authors: XM
authors: Shen
authors: Guo-Yao
authors: GY
authors: Tang
mesh_terms: D000906:Antibodies; D017951:Antigen Presentation / Q000276:immunology; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D004396:Coloring Agents; D004848:Epithelium / Q000187:drug effects / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000032:analysis / Q000494:pharmacology; D007376:Interleukin-2 / Q000032:analysis; D015603:Keratinocytes / Q000187:drug effects / Q000276:immunology; D017676:Lichen Planus, Oral / Q000097:blood / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D009061:Mouth Mucosa / Q000276:immunology; D010835:Phytohemagglutinins / Q000494:pharmacology; D061027:Programmed Cell Death 1 Ligand 2 Protein / Q000276:immunology*; D060888:Real-Time Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D000906:Antibodies; D004396:Coloring Agents; D007376:Interleukin-2; C556977:PDCD1LG2 protein, human; D010835:Phytohemagglutinins; D061027:Programmed Cell Death 1 Ligand 2 Protein; D013778:Tetrazolium Salts; D013844:Thiazoles; D007371:Interferon-gamma; C022616:thiazolyl blue