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Fcγ receptors mediate internalization of anti‐Ro and anti‐La autoantibodies from Sjögren’s syndrome and apoptosis in human salivary gland cell line A‐253
Author(s) -
Lisi Sabrina,
Sisto Margherita,
Soleti Raffaella,
Saponaro Concetta,
Scagliusi Pasquale,
D’Amore Massimo,
Saccia Matteo,
Maffione Angela B.,
Mitolo Vincenzo
Publication year - 2007
Publication title -
journal of oral pathology and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 83
eISSN - 1600-0714
pISSN - 0904-2512
DOI - 10.1111/j.1600-0714.2007.00563.x
Subject(s) - autoantibody , receptor , microbiology and biotechnology , salivary gland , autoimmune disease , apoptosis , immunology , western blot , biology , antibody , chemistry , pathology , medicine , biochemistry , gene
Background: The presence of serum anti‐Ro and anti‐La autoantibodies directed against the ribonucleoproteins Ro and La has been associated with Sjögren’s syndrome (SS), an autoimmune rheumatic disease that targets salivary and lachrymal glands. There is increasing evidence of the direct involvement of autoantibodies in the pathogenesis of tissue injury and correlation of their presence with clinical manifestations in SS. The focus of this work was to explore the cellular apoptotic pathway triggered by binding and penetration of anti‐Ro and anti‐La autoantibodies in human salivary gland cell line A‐253 and to identify the membrane receptors through which anti‐Ro and anti‐La could exert their effect. Methods: Anti‐Ro and anti‐La autoantibodies were purified from IgG fractions, obtained from eleven healthy volunteers and patients with primary Sjögren’s syndrome, using Sepharose 4B‐Ro and Sepharose 4B‐La affinity columns. Flow cytometry, RT‐PCR, western blot and confocal microscopy analysis were used to visualize the FCγRI, FCγRII and FCγRIII receptors on the A‐253 cell membrane. DNA laddering and western blot analysis of caspases activation were studied to evaluate in A‐253 cells treated with anti‐Ro and anti‐La autoantibodies. Results: The results yeilded the evidence of the presence of members of the Fcγ receptors (FcγRs) family on the cell membrane of the human salivary gland cell line A‐253. Furthermore, we demonstrated that, in the A‐253 cell line, anti‐Ro and anti‐La autoantibodies can access the cells probably through Fcγ receptors, and trigger apoptotis. Conclusions: We conclude that anti‐Ro and anti‐La autoantibodies have pathogenic effects that could depend on binding to Fcγ receptors.