Characteristic epitope recognition pattern of autoantibodies against eukaryotic ribosomal protein L7 in systemic autoimmune diseases.
OBJECTIVE
To define the epitope-recognition pattern and the fine specificity of the autoantibody response to protein L7 in patients with rheumatic diseases.


METHODS
The epitope-recognition pattern was studied by enzyme-linked immunosorbent assay utilizing overlapping fragments of L7. The fine specificity was examined by binding inhibition and isoelectric focusing.


RESULTS
We observed a disease-specific epitope-recognition pattern of anti-L7 autoantibodies. There was one immunodominant epitope that was recognized by all anti-L7-positive sera from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and systemic sclerosis (SSc). Additional recognition of minor epitopes was observed; it arises by intramolecular epitope spreading and was correlated with disease activity in SLE patients. SSc patients differed from SLE and RA patients in that their sera did not recognize certain minor epitopes. The major epitope was recognized by high-affinity autoantibodies of limited heterogeneity. Minor epitopes were recognized by heterogeneous low-affinity autoantibodies.


CONCLUSIONS
The anti-L7 autoantibody response is oligoclonal. Additional B cell clones are activated by antigen during active phases of disease.
Neu
E
E
Universität Konstanz, Germany.
Hemmerich
P H
PH
Peter
H H
HH
Krawinkel
U
U
von Mikecz
A H
AH
D000293:Adolescent; D001172:Arthritis, Rheumatoid / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis*; D001327:Autoimmune Diseases / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D010446:Peptide Fragments / Q000276:immunology; D012269:Ribosomal Proteins / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000276:immunology; D012680:Sensitivity and Specificity
D001323:Autoantibodies; D000939:Epitopes; D010446:Peptide Fragments; C053634:RPL7 protein, human; D012269:Ribosomal Proteins