SS-56, a novel cellular target of autoantibody responses in Sjögren syndrome and systemic lupus erythematosus.
Certain autoimmune disorders, including Sjögren syndrome (SS) and systemic lupus erythematosus (SLE), are characterized by autoantibodies against the Ro/SSA and La/SSB cellular antigens. Although the implication of these autoantibodies in disease pathogenesis is still unclear, it is believed that the aberrant responses against autoantigens may extend to other proteins that are not yet well defined. In an attempt to analyze the regulated gene expression in lymphocytes by an HIV-suppressive immunomodulator, we have identified and cloned a novel gene encoding a 56-kDa protein, named SS-56, which is structurally related to the 52-kDa Ro/SSA antigen. The new protein showed primarily perinuclear cytoplasmic localization, and recombinant SS-56 was found to react in ELISA with sera from most patients with SS or SLE. Western blot analysis confirmed the autoantigenic nature of native SS-56 in extracts from HeLa cells. Interestingly, the incidence of antibodies to SS-56 was associated with visceral complications in SLE, and roughly half of the 17 SS or SLE patients with no detectable antibodies to SSA and SSB antigens presented measurable antibodies against recombinant SS-56. Thus, SS-56 represents a new member of the SS family of autoantigens and could become an additional and important diagnostic marker for SS and SLE.
Billaut-Mulot
O
O
Laboratory of Molecular Immunology of Infection and Inflammation, Institut Pasteur de Lille, Lille, France.
Cocude
C
C
Kolesnitchenko
V
V
Truong
M J
MJ
Chan
E K
EK
Hachula
E
E
de la Tribonnière
X
X
Capron
A
A
Bahr
G M
GM
D000328:Adult; D000595:Amino Acid Sequence; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D015415:Biomarkers; D016022:Case-Control Studies; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D015658:HIV Infections / Q000276:immunology; D006367:HeLa Cells; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000235:genetics / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000235:genetics / Q000276:immunology*; D017386:Sequence Homology, Amino Acid; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000235:genetics / Q000276:immunology*; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases; D000099207:SS-A Antigen
D001323:Autoantibodies; D001324:Autoantigens; D015415:Biomarkers; D018076:DNA, Complementary; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases; D000099207:SS-A Antigen; C116006:RO60 protein, human; C437970:TRIM68 protein, human