SERUM ANTIBODIES FROM PATIENTS WITH PRIMARY SJOGRENS-SYNDROME AND SYSTEMIC LUPUS-ERYTHEMATOSUS RECOGNIZE MULTIPLE EPITOPES ON THE LA(SS-B) AUTOANTIGEN RESEMBLING VIRAL PROTEIN SEQUENCES

The aim of this study was to investigate the epitope recognition patte rn of La(SS-B) autoantibodies in sera from patients with Sjogren's syn drome (SS) and systemic lupus erythematosus (SLE) using overlapping sy nthetic decapeptides on solid phase. Eighty different decapeptides wit h five amino acids overlap from the human La(SS-B) autoantigen were sy nthesized on cellulose paper using F-moc chemistry. Tests were perform ed with 14 SS and six SLE sera. The results showed that the immune res ponse to the La(SS-B) oligopeptides was restricted and unique for each individual with no particular pattern typical for each of the two dis eases, apart from the fact that SLE sera gave positive reaction with f ewer peptides. Regions within the N- and C-termini harboured most of t he positive sequences. The authors specifically addressed the possibil ity of a viral aetiology for disease development or autoantibody gener ation. In this context the most frequently recognized linear epitopes on the La(SS-B) autoantigen showed sequence similarities with proteins from a range of ubiquitous human viruses, in particular from the herp es virus group. The La(SS-B) autoantibodies may thus be generated thro ugh molecular mimicry.