title: Selective response of dermal Th-1 cells to 20-50 kDa streptococcal cell-wall proteins in chronic plaque psoriasis.
abstract: We have recently described a dermal Th-1 subset in skin lesions of psoriasis which recognizes cell-wall extract isolated from group A streptococci (GAS). As a first step in the identification of the streptococcal proteins involved, dermal T-cell lines (TCL) cultured from the lesional skin of 12 human leucocyte antigen (HLA)-typed psoriasis patients were stimulated with GAS cell-wall extract and 14 fractions (MWt approximately 20-100 kDa) separated from the cell-wall extract by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and electroelution, stained for intracellular interferon-gamma(IFN-gamma) expression and analysed by flow cytometry. All the TCL responded to GAS cell-wall extract to varying extents (3.5-27.6% IFN-gamma+). This response was consistently directed against 20-50 kDa cell-wall fractions and inhibited by anti-HLA-DR antibody. TCL with higher responses to GAS cell-wall extract recognized a larger number of fractions within this range than the lower responder TCL. No difference between the level and pattern of response to the fractions was observed for TCL from HLA-DR7+ (n = 6) and HLA-DR7- (n = 6) individuals. This preliminary study has shown a selective response to lower MWt proteins expressed on GAS cell wall by skin Th-1 cells in psoriasis. Further studies are required to identify the proteins involved.
authors.affiliation: Department of Dermatology, Faculty of Medicine, St Mary's Campus, Imperial College of Science, Technology & Medicine, London, UK. b.baker@imperial.ac.uk
authors.forename: B S
authors.initials: BS
authors.lastname: Baker
authors.forename: J-M
authors.initials: JM
authors.lastname: Ovigne
authors.forename: V A
authors.initials: VA
authors.lastname: Fischetti
authors.forename: A
authors.initials: A
authors.lastname: Powles
authors.forename: L
authors.initials: L
authors.lastname: Fry
mesh_terms: D000328:Adult; D000368:Aged; D017951:Antigen Presentation / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology* / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology* / Q000494:pharmacology; D002460:Cell Line; D002473:Cell Wall / Q000276:immunology / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes; D005260:Female; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000276:immunology* / Q000382:microbiology; D012867:Skin / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D013290:Streptococcal Infections / Q000276:immunology*; D013291:Streptococcus / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology* / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes; D006684:HLA-DR Antigens