title: Ultraviolet B-exposed major histocompatibility complex class ii positive keratinocytes and antigen-presenting cells demonstrate a differential capacity to activate T cells in the presence of staphylococcal superantigens.
abstract: In this study we tested the capacity of ultraviolet B (UVB)-irradiated major histocompatibility complex (MHC) class II+ keratinocytes, monocytes and dendritic cells to activate T cells in the presence of Staphylococcus enterotoxin B. We demonstrated that UVB irradiation of MHC class II+ keratinocytes does not change their capacity to activate T cells in the presence of Staphylococcus enterotoxin B. In contrast, UVB irradiation of antigen-presenting cells decreases their capacity to activate T cells. This differential capacity to activate T cells after UVB irradiation was not due to factors released from UVB-irradiated cells. The interferon-gamma induced upregulation of HLA-DR and intercellular adhesion molecule-1 on keratinocytes does not seem to be the only explanation, since UVB irradiation decreased the accessory cell function of interferon-gamma pretreated monocytes. Differential requirements for and UVB regulation of costimulatory molecules may be involved, since blocking of the B7/CD28 pathway affects the capacity of dendritic cells but not keratinocytes to activate T cells in the presence of Staphylococcus enterotoxin B. Thus, MHC class II+ keratinocytes in the presence of superantigens released from staphylococci may activate T cells and maintain inflammation despite UVB treatment.
authors: Department of Dermatology, University of Copenhagen, Hellerup, Denmark.
authors: L
authors: L
authors: Skov
authors: O
authors: O
authors: Baadsgaard
mesh_terms: D000328:Adult; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000528:radiation effects*; D018929:Cell Culture Techniques; D003713:Dendritic Cells / Q000276:immunology / Q000528:radiation effects; D004768:Enterotoxins / Q000276:immunology*; D006681:HLA-D Antigens / Q000032:analysis; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D015603:Keratinocytes / Q000276:immunology / Q000528:radiation effects*; D008213:Lymphocyte Activation / Q000528:radiation effects*; D009000:Monocytes / Q000276:immunology / Q000528:radiation effects; D011994:Recombinant Proteins; D013211:Staphylococcus aureus / Q000276:immunology; D018089:Superantigens / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014466:Ultraviolet Rays
chemical_list: D004768:Enterotoxins; D006681:HLA-D Antigens; D011994:Recombinant Proteins; D018089:Superantigens; C031818:enterotoxin B, staphylococcal; D007371:Interferon-gamma