Antibodies against nitric oxide damaged poly L-tyrosine and 3-nitrotyrosine levels in systemic lupus erythematosus.
Alterations in the amino acid structure or sequence can generate neo-epitopes from self-proteins causing autoaggressive immune attack. Reactive nitrogen species are an important factor that induces post-translational modification of proteins by cellular reduction and oxidation mechanism; cysteinyl-nitrosylation or tyrosine nitration leading to potentially pathogenic pathways. It was thought of interest to investigate the immunogenicity of nitrated poly L-tyrosine vis-á-vis its possible role in the induction of antibodies in systemic lupus erythematosus (SLE). Commercially available poly L-tyrosine was exposed to nitrating species and the damage was monitored by UV spectroscopy and alkaline gel electrophoresis. The results indicated the formation of 3-nitrotyrosine. Nitrated poly L-tyrosine induced higher titre antibodies as compared to the native form. Nitrated poly L-tyrosine was recognized by the autoantibodies present in the sera of patients suffering from SLE by enzyme immunoassays and band shift assay. The possible role of nitrated self-proteins has been discussed in the production of circulating anti-DNA antibodies in SLE.
Department of Biochemistry, Faculty of Medicine, A.M.U. Aligarh-202002, UP, India.
Fozia
F
Khan
Rashid
R
Ali
D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions; D001323:Autoantibodies / Q000097:blood*; D004247:DNA / Q000276:immunology; D004587:Electrophoresis, Agar Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology*; D009569:Nitric Oxide / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry* / Q000276:immunology*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000276:immunology
D001323:Autoantibodies; D010455:Peptides; C017663:polytyrosine; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D004247:DNA