A recombinant topoisomerase I used for autoantibody detection in sera from patients with systemic sclerosis.
We report the expression of a cDNA clone encoding 695 carboxyl-terminal amino acids of human DNA topoisomerase I (topoI) in Escherichia coli. More than 96% of the anti-HeLa topoI-positive sera from patients with a connective tissue disease displayed also an immunoreactivity with this recombinant protein (the HTopoA protein). Sera from patients with a definite diagnosis systemic sclerosis and reacting with HeLa topoI, all reacted with the HTopoA protein as well. Sera from patients with systemic sclerosis that did not contain anti-topoI antibodies (about 30% of the systemic sclerosis sera), as concluded from HeLa immunoblot, displayed also no immunoreactivity with our recombinant antigen. By expressing different fragments of HTopoA, we were able to assign at least three different autoimmune epitope regions on the HTopoA protein and we show that over a period of 5 years the amount of anti-topoI antibodies against these regions may fluctuate.
Department of Biochemistry, University of Nijmegen, The Netherlands.
R
R
Verheijen
F
F
Van den Hoogen
R
R
Beijer
A
A
Richter
E
E
Penner
W J
WJ
Habets
W J
WJ
van Venrooij
D000595:Amino Acid Sequence; D001323:Autoantibodies / Q000032:analysis*; D001483:Base Sequence; D003001:Cloning, Molecular; D004264:DNA Topoisomerases, Type I / Q000276:immunology; D004274:DNA, Recombinant; D000939:Epitopes / Q000032:analysis; D006801:Humans; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000276:immunology; D012595:Scleroderma, Systemic / Q000276:immunology*
D001323:Autoantibodies; D004274:DNA, Recombinant; D000939:Epitopes; D011993:Recombinant Fusion Proteins; D004264:DNA Topoisomerases, Type I