A novel epitope on the C-terminus of SmD1 is recognized by the majority of sera from patients with systemic lupus erythematosus

Gabriela Riemekasten*, Jeannette Marell, Grit Trebeljahr, Rolf Klein, Gert Hausdorf, Thomas Häupl, Jens Schneider-Mergener, Gerd R. Burmester, Falk Hiepe

*Corresponding author for this work
84 Citations (Scopus)


The SmD1 protein is a specific target for the autoantibody response in SLE. To further analyze this reactivity epitope, mapping was performed with cellulose-bound 13-mer peptides overlapping 10 amino acids (aa). In this initial approach, 4 out of 15 SLE sera recognized more than five overlapping peptides of the SmD1 C-terminus. Therefore, longer oligopeptides of up to 37 aa of this region were generated and probed for as antigens by ELISA. For the SmD1 aa 83-119 polypeptide, there was a striking increase of reactivity with 70.0% positive reactions out of 167 SLE sera. In contrast, 105 healthy control sera were negative, and only 8.3% of sera from patients with other inflammatory diseases (n = 267) exhibited a response, which was of low level only. The anti-SmD183-119 reactivity was significantly higher in anti- dsDNA antibody positive vs. negative sera (P < 0.001) and correlated with disease activity. Four of five human monoclonal anti-dsDNA antibodies also reacted with SmD183-119. The specificity for SmD1 was demonstrated by inhibition experiments and immunization of rabbits with SmD183-119 inducing SmD1-specific antibodies. In conclusion, the SmD183-119 peptide was demonstrated to be an important and highly specific target of the autoimmune response in SLE. The high sensitivity of this ELISA probably depends on a conformational epitope, which appears not to be accessible in the full-size SmD1 protein.

Original languageEnglish
JournalJournal of Clinical Investigation
Issue number4
Pages (from-to)754-763
Number of pages10
Publication statusPublished - 15.08.1998

Research Areas and Centers

  • Academic Focus: Center for Infection and Inflammation Research (ZIEL)


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