Detection, epitope-mapping and function of anti-Fas autoantibody in patients with silicosis.
Dysregulation of apoptosis through the Fas-Fas ligand pathway is associated with the onset of autoimmune disease. Since autoantibodies directed against unknown antigens are present in the sera of these patients, sera samples were examined for the presence of autoantibodies directed against the Fas molecule. Using Western blotting and a ProteinChip analysis, autoantibodies against Fas were detected in patients with silicosis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), and weakly detected in healthy individuals. Using epitope mapping employing 12-amino-acid polypeptides with the SPOTs system, a minimum of four epitopes and a maximum of 10 epitopes were found. Several amino acid residues involved in binding FasL, such as C66, R87, L90, E93 and H126, were presented within the epitopes. Serum containing a large amount of anti-Fas autoantibody from silicosis patients inhibited the growth of a Fas-expressing human cell line, but did not inhibit the growth of a low Fas-expresser nor a Fas-expresser in which the Fas gene had been silenced by small interference RNA. All epitopes in the intracellular region of Fas were located in the death domain. The possible roles of anti-Fas autoantibody detected in healthy volunteers and patients with silicosis or autoimmune diseases are discussed here.
Takata-Tomokuni
Akiko
A
Department of Hygiene, Kawasaki Medical School, Kurashiki, Japan.
Ueki
Ayako
A
Shiwa
Mieko
M
Isozaki
Yumika
Y
Hatayama
Tamayo
T
Katsuyama
Hironobu
H
Hyodoh
Fuminori
F
Fujimoto
Wataru
W
Ueki
Hiroaki
H
Kusaka
Masayasu
M
Arikuni
Hisashi
H
Otsuki
Takemi
T
D000368:Aged; D000369:Aged, 80 and over; D000596:Amino Acids / Q000032:analysis; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology*; D015153:Blotting, Western / Q000379:methods; D002455:Cell Division; D018604:Epitope Mapping; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008297:Male; D008875:Middle Aged; D040081:Protein Array Analysis / Q000379:methods; D034741:RNA, Small Interfering / Q000235:genetics; D012595:Scleroderma, Systemic / Q000276:immunology; D012829:Silicosis / Q000276:immunology*; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D000596:Amino Acids; D001323:Autoantibodies; D034741:RNA, Small Interfering; D019014:fas Receptor