Clinical Significance of Antibodies to Native or Denatured 60‐kd or 52‐kd Ro/SS‐A Proteins in Sjögren's Syndrome

Tsuzaka, Kensei; Fujii, Tomoyuki; Akizuki, Masashi; Mimori, Tsuneyo; Tojo, Takeo; Fujii, H.; Tsukatani, Y; Kubo, Atsushi; Homma, Mitsuo

doi:10.1002/art.1780370113

Cited by 31 publications

(22 citation statements)

References 12 publications

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“…The remaining 16 were very weak or negative (data not shown), presumably because they contained Abs at levels below the threshold for detection by immunoblotting or that were directed against conformational epitopes, which were lost when the Ag was subjected to SDS-PAGE. The presence of Abs directed against conformational epitopes is common in other autoantigen systems (40,41). ELISA-negative sera were very weak or negative when rescreened by immunoblotting (Fig.…”

Section: Rescreening and Determination Of Subunit Specificity By Immumentioning

confidence: 92%

Identification of Human Autoantibodies to the DNA Ligase IV/XRCC4 Complex and Mapping of an Autoimmune Epitope to a Potential Regulatory Region

Lee

Dong

Wang

et al. 2002

The Journal of Immunology

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The nonhomologous end-joining pathway is the principal mechanism for repair of ionizing radiation-induced, double-strand breaks in mammalian cells. Three polypeptides in this pathway, including the two subunits of Ku protein and the catalytic subunit of the DNA-dependent protein kinase, are known targets of autoantibodies in systemic rheumatic diseases. Here we show that two additional polypeptides in the pathway, DNA ligase IV and XRCC4, are also targets of autoantibodies. These Abs were present in 20% of patients with systemic lupus erythematosus and overlap syndrome. Previous work has shown that XRCC4 is subject to radiation-induced post-translational modification, including phosphorylation by DNA-dependent protein kinase and cleavage by caspase 3. We mapped a major autoimmune epitope in XRCC4 and found that it encompassed a DNA-dependent protein kinase phosphorylation site, which is located at serine 260; that it was adjacent to a site for caspase 3, which cleaves after residue 265; and that it also spanned a site for the inflammatory protease, granzyme B, which cleaves after residue 254. The finding that five different polypeptides in the nonhomologous end-joining pathway are potential targets of autoantibodies together with the observation that one of the autoimmune epitopes in XRCC4 coincides with a sequence that is a nexus for radiation-induced regulatory events suggest that exposure to agents that introduce DNA double-strand breaks may be one of the factors that influences the development of an autoimmune response in susceptible individuals.

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Section: Rescreening and Determination Of Subunit Specificity By Immumentioning

confidence: 92%

Identification of Human Autoantibodies to the DNA Ligase IV/XRCC4 Complex and Mapping of an Autoimmune Epitope to a Potential Regulatory Region

Lee

Dong

Wang

et al. 2002

The Journal of Immunology

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“…Serum levels of IgM were significantly correlated with those of sFas/ APO-1 in 1 ~ SS patients (r 2 = 0.632, p=0.002). It has been reported that levels of IgM are higher in sera from 1 ~ SS patients with extraglandular diseases such as pulmonary fibrosis [22]. The level of sFas/APO-1 was thus compared between extraglandular disease-positive and -negative groups.…”

Section: Relationship Between Sfas/apo-1 and Various Laboratory Parammentioning

confidence: 99%

Serum soluble Fas/APO-1 is increased in patients with primary Sj�gren's syndrome

et al. 1998

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The aim of the study was to elucidate the involvement of Fas antigen in human autoimmune disease, by analysing serum levels of soluble Fas/APO-1 protein in patients with various autoimmune diseases, including system lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM), Behçet's syndrome and Sjögren's syndrome (SjS). The levels of soluble Fas/APO-1 in sera were quantitated by a sandwich enzyme-linked immunosorbent assay. Soluble Fas/APO-1 levels were significantly increased in serum from patients with primary Sjögren's syndrome (primary SjS) compared with control subjects. However, no significant differences in soluble Fas/APO-1 levels were noted in patients with secondary Sjögren's syndrome (secondary SjS) nor in patients with any of the other autoimmune diseases. The soluble Fas/APO-1 level in primary SjS patients with extraglandular diseases was significantly higher than that in patients without extraglandular diseases. These results suggest that soluble Fas/APO-1 protein may play an important role in the pathogenesis of primary SS.

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“…The most common assays used in clinical practice to detect autoantibodies are DID and ELISA using recombinant or native proteins. Because autoantibodies most frequently target conformational determinants on native proteins and RNP particles [1,[14][15][16], the most sensitive and specific assay for the detection of autoantibodies targeting RNP particles remains IPP of cell extracts followed by visualization of the precipitated RNAs or proteins in denaturing polyacrylamide gels [15]. However, the reliability of IPP is offset by its tediousness and poor quantification.…”

Section: Discussionmentioning

confidence: 99%

RNA-labelled Ro and La ribonucleoprotein complexes reassembled in vitro; characterization by gel shift analysis

Granger

Gendron

Tremblay

et al. 1996

Clinical and Experimental Immunology

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SUMMARYRo and La RNP complexes were reassembled from in vitro labelled hY5 RNA and HeLa cell extracts. These complexes were then visualized through retardation of migration of labelled hY5 RNA in nondenaturing polyacrylamide gels. Three major complexes (named A, B, and C) were formed when crude cellular extracts (S100 fraction) were used. Using monospecific anti-60-kD Ro (Ro60) and anti-La antibodies to retard RNPs containing these antigens during migration in the gels, the three major complexes were shown to contain Ro60 (C), La (B), or both proteins (A). The specificity of RNAprotein interactions in the reassembled complexes was further demonstrated using two 3 0 -shortened hY5 RNA transcripts lacking the La-binding site (hY5-Alu I RNA) and both the Ro60 and La-binding sites (hY5-Hha I RNA). hY5-Hha I RNA still formed a single, minor complex when incubated with S100 extract, suggesting interaction with a yet undefined protein. In addition, we used the capacity of specific antibodies to retard the migration of the ressembled complexes to design a detection assay for anti-Ro and anti-La autoantibodies. Using 84 human sera, our assay was shown to approximate the specificity and sensitivity of an immunoprecipitation assay where 32 P-labelled cell extracts are used as source of antigens. Our assay may be used to detect low levels of antibodies to conformational determinants on Ro60 and La proteins in human sera and antibody preparations.

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Clinical Significance of Antibodies to Native or Denatured 60‐kd or 52‐kd Ro/SS‐A Proteins in Sjögren's Syndrome

Cited by 31 publications

References 12 publications

Identification of Human Autoantibodies to the DNA Ligase IV/XRCC4 Complex and Mapping of an Autoimmune Epitope to a Potential Regulatory Region

Identification of Human Autoantibodies to the DNA Ligase IV/XRCC4 Complex and Mapping of an Autoimmune Epitope to a Potential Regulatory Region

Serum soluble Fas/APO-1 is increased in patients with primary Sj�gren's syndrome

RNA-labelled Ro and La ribonucleoprotein complexes reassembled in vitro; characterization by gel shift analysis

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