title: Lymphocyte responses to DR1/4 restricted peptides in rheumatoid arthritis.
abstract: OBJECTIVE
  To determine whether analog and unrelated DR1/4 binding peptides alter DR1/4 restricted responses of peripheral blood lymphocytes (PBL) from patients with rheumatoid arthritis (RA).
  
  
  METHODS
  PBL from 25 patients with RA and 12 healthy controls were cultured with DR1/4 restricted peptides of the influenza haemagglutinin, amino acids 307-319 (HA) and matrix proteins, amino acids 17-29 (IM). Responses were determined by 3H-thymidine uptake proliferation assays and limiting dilution analysis. Competitor peptides were analogs HA-R312 and HA-K313 differing from HA by one amino acid at the 312 or 313 position respectively or unrelated peptides which bind to DR1/4.
  
  
  RESULTS
  The responses of eight patients with RA to the two stimulatory influenza peptides did not differ significantly from controls and this was confirmed by the frequency estimate of T cells in PBL which responded to HA (mean frequency: 1 in 9.0 x 10(4), n = 5, in DR1/4+ RA patients, 1 in 7.6 x 10(4), n = 5, in DR1/4+ healthy controls). DR1/4 binding analogs of the HA peptide inhibited HA specific peptide responses of PBL from patients with RA and controls. Inhibition was also detected with unrelated peptides which bind to DR1/4 but to which the individual did not respond.
  
  
  CONCLUSIONS
  Similar responses to two DR1/4 restricted peptides were observed in patients with RA and controls. Both antigen analog- and unrelated peptide-major histocompatibility complexes (MHC) can result in the inhibition of antigen specific responses in multi-clonal human lymphocyte populations. However, an analog peptide may be stimulatory in some individuals. These results provide some initial data for the development of a rational approach to MHC-specific immunomodulation in rheumatoid arthritis.
authors.affiliation: Department of Molecular Medicine, University of Auckland, School of Medicine, New Zealand.
authors.forename: M A
authors.initials: MA
authors.lastname: Skinner
authors.forename: L
authors.initials: L
authors.lastname: Watson
authors.forename: A
authors.initials: A
authors.lastname: Geursen
authors.forename: P L
authors.initials: PL
authors.lastname: Tan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D001667:Binding, Competitive; D002455:Cell Division; D005260:Female; D006684:HLA-DR Antigens / Q000276:immunology*; D015798:HLA-DR1 Antigen / Q000276:immunology; D015804:HLA-DR4 Antigen / Q000276:immunology; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology*; D011485:Protein Binding; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006684:HLA-DR Antigens; D015798:HLA-DR1 Antigen; D015804:HLA-DR4 Antigen; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D010455:Peptides