An immunodominant epitope on DNA topoisomerase I is conformational in nature: Heterogeneity in its recognition by systemic sclerosis sera
✍ Scribed by Masataka Kuwana; Junichi Kaburaki; Thomas A. Medsger Jr.; Timothy M. Wright
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 233 KB
- Volume
- 42
- Category
- Article
- ISSN
- 0004-3591
No coin nor oath required. For personal study only.
✦ Synopsis
Objective:
To characterize an immunodominant epitope recognized by anti-dna topoisomerase i (topo i) antibody, a major autoantibody in sera of patients with systemic sclerosis (ssc).
Methods:
Topo i fragments were generated as fusion proteins using a bacterial expression system as well as polypeptides translated in vitro using a eukaryotic expression system. reactivities to the 2 preparations of recombinant topo i polypeptides in anti-topo i-positive sera from ssc patients of varied ethnic backgrounds were examined by immunoblotting, immunoprecipitation, and/or enzyme-linked immunosorbent assay.
Results:
The fragment encoding amino acids 489-573 of topo i was recognized by 98 of 100 anti-topo i-positive ssc sera. both carboxyl- and amino-terminal deletion studies as well as competitive inhibition assays using topo i synthetic peptides showed that a region of > or =52 amino acids (512-563) was necessary for recognition by anti-topo i antibodies. the minimum epitope region and conformation required for this reactivity were variable among sera from caucasian, african american, japanese, and choctaw ssc patients.
Conclusion:
An immunodominant epitope recognized by anti-topo i autoantibody is located in the region of amino acids 489-573 of the topo i protein and is largely conformational in nature. the recognition pattern of this region by anti-topo i-positive sera is heterogeneous and is influenced by ethnic background.