Absence of autoantibodies against correctly folded recombinant fibrillin-1 protein in systemic sclerosis patients.
Autoantibodies against short recombinant fragments of fibrillin-1 produced in bacterial expression systems have been found in tight-skin mouse, systemic sclerosis, mixed connective tissue disease, and primary pulmonary hypertension syndrome. In patients with scleroderma, the frequency of anti-fibrillin-1 antibodies was 42% in Caucasians. Until now it has been unclear whether this immune response has a primary function in disease pathogenesis or is a secondary phenomenon. In the present study we analyzed the frequency of autoantibodies against two overlapping recombinant polypeptides spanning the N-terminal and C-terminal halves of human fibrillin-1, which were produced in human embryonic kidney (HEK-293) cells. Correct three-dimensional structures of the recombinant fibrillin-1 polypeptides were shown by electron microscopy and immunoreactivity with antibodies. Screening of fibrillin-1 antibodies was performed in 41 sera from systemic sclerosis patients and in 44 healthy controls with a Caucasian background. Microtiter plates were coated with the recombinant polypeptides of fibrillin-1 and incubated with 1:100 diluted sera. Positive binding was defined as being more than 2 SD above the mean of the control group. ELISAs showed that none of the sera of patients with systemic sclerosis contained autoantibodies against the N-terminal or C-terminal recombinant fibrillin-1 polypeptide. The data show the absence of autoantibodies against recombinant fibrillin-1 protein in Caucasian systemic sclerosis patients. Because the correct three-dimensional folding of the recombinant proteins has been substantiated by several independent methods, we conclude that autoantibodies against correctly folded fibrillin are not a primary phenomenon in the pathogenesis of systemic sclerosis.
Brinckmann
Jürgen
J
Department of Dermatology, University of Lübeck, Lübeck, Germany. brinckmann@molbio.uni-luebeck.de
Hunzelmann
Nico
N
El-Hallous
Ehab
E
Krieg
Thomas
T
Sakai
Lynn Y
LY
Krengel
Sven
S
Reinhardt
Dieter P
DP
D001323:Autoantibodies / Q000097:blood; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000276:immunology / Q000648:ultrastructure; D005260:Female; D000071838:Fibrillin-1; D000071837:Fibrillins; D006801:Humans; D008297:Male; D008840:Microfilament Proteins / Q000737:chemistry / Q000276:immunology / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D012595:Scleroderma, Systemic / Q000097:blood / Q000276:immunology*; D054392:Adipokines
D001323:Autoantibodies; D016326:Extracellular Matrix Proteins; D000071838:Fibrillin-1; D000071837:Fibrillins; D008840:Microfilament Proteins; D011994:Recombinant Proteins; C000605722:FBN1 protein, human; D054392:Adipokines; C000605724:Fbn1 protein, mouse