Anti-ribosomal antibodies bind the Sm proteins D and B/B'.
In order to analyse the specificity of human anti-ribosomal P protein antibodies, anti-ribosomal P protein antibodies were affinity-purified from the sera of lupus patients. Their binding capacity towards recombinant SmD protein and recombinant SmB/B' protein was evaluated by immunoblot and ELISA. Epitope mapping of SmD was performed by means of synthetic peptides. Anti-ribosomal P protein antibodies bound recombinant SmD (5/10) and SmB/B' (4/10) on immunoblot; 6/10 showed binding capacity to SmD on ELISA. Inhibition experiments using ELISA confirmed the specificity of this binding. Our data indicate the cross-reactivity of spontaneously developed anti-ribosomal P protein antibodies with the B/B' and D constituents of the Sm complex. The coexistence of anti-Sm and anti-ribosomal antibodies in lupus sera may therefore be due, at least in part, to the reactivity of a single autoantibody population.
Caponi
L
L
Clinical Immunology Unit, Istituto di Patologia Medica, University of Pisa, Italy.
Bombardieri
S
S
Migliorini
P
P
D000918:Antibody Specificity; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001324:Autoantigens / Q000235:genetics / Q000276:immunology*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology*; D015800:Protozoan Proteins; D011961:Receptors, Fc / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000276:immunology*; D012269:Ribosomal Proteins / Q000276:immunology; D012270:Ribosomes / Q000276:immunology*; D055517:snRNP Core Proteins
D001323:Autoantibodies; D001324:Autoantigens; C045281:IgA receptor; C064601:L12E protein, Trypanosoma cruzi; D015800:Protozoan Proteins; D011961:Receptors, Fc; D011994:Recombinant Proteins; D017411:Ribonucleoproteins, Small Nuclear; D012269:Ribosomal Proteins; C526407:SNRPB protein, human; D055517:snRNP Core Proteins