title: Inhibitory effects on HLA-DR1-specific T-cell activation by influenza virus haemagglutinin-derived peptides.
abstract: Collagen (CII) 263-272 peptide, an autoantigen in rheumatoid arthritis, is a specific human leukocyte antigen (HLA)-DR1/4-binding peptide recognized by T-cell receptors (TCR). The affinity of influenza virus haemagglutinin (HA) 306-318 peptide for the antigen-binding groove of HLA-DR1/4 molecules is higher than that of CII263-272. The HLA-DR1/4-binding residues of HA306-318 are located in the region 308-317. Altered HA308-317 peptides with substitutions of TCR-contact residues may inhibit HLA-DR1/4-specific T-cell activation by blocking the antigen-binding site of HLA-DR1/4 molecules. To evaluate the role of altered HA308-317 peptides in HLA-DR1-restricted T-cell activation, we synthesized three altered HA308-317 peptides. The specific binding of altered HA308-317 peptides to HLA-DR1 molecules was examined using flow cytometry. Effects of altered HA308-317 peptides on HLA-DR1-specific T-cell hybridoma were studied by measuring T-cell proliferation and surface expression of CD69 or CD25. The results showed that altered HA308-317 peptides were able to bind to HLA-DR1 molecules and competed with CII263-272 or wildtype HA308-317 peptide. Compared with wildtype CII263-272 or HA308-317, altered HA308-317 peptides did not stimulate significant T-cell proliferation and CD69 or CD25 expression. Furthermore, the altered HA308-317 peptides inhibited HLA-DR1-specific T-cell activation induced by CII263-272 or wildtype HA308-317 peptide, which may suggest an effective therapeutic strategy in inhibition of HLA-DR1-specific T-cell responses in autoimmunity.
authors.affiliation: Department of Rheumatology and Immunology, People's Hospital, Beijing University, China.
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Li
authors.forename: Z
authors.initials: Z
authors.lastname: Li
mesh_terms: D019943:Amino Acid Substitution; D003198:Computer Simulation; D015798:HLA-DR1 Antigen / Q000187:drug effects* / Q000378:metabolism; D015804:HLA-DR4 Antigen / Q000187:drug effects* / Q000378:metabolism; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D006801:Humans; D008213:Lymphocyte Activation; D010455:Peptides / Q000138:chemical synthesis / Q000235:genetics / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism
chemical_list: D015798:HLA-DR1 Antigen; D015804:HLA-DR4 Antigen; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D010455:Peptides