Volume 5 Supplement 1

23rd European Workshop for Rheumatology Research

Open Access

Linear epitopes of two different autoantigens (La/SSB and myelin basic protein) with a high degree of molecular similarity cause different humoral responses

  • A Terzoglou1,
  • JG Routsias1,
  • C Sakarellos1,
  • M Sakarellos-Daitsiotis1,
  • HM Moutsopoulos1 and
  • AG Tzioufas1
Arthritis Res Ther20035(Suppl 1):27

https://doi.org/10.1186/ar657

Received: 14 January 2003

Published: 24 February 2003

Backgkround

Sequences 147–154aa of La/SSB and 139–146aa of human myelin basic protein (MBP) present 83% sequence similarity.

Objective

We investigated the immune response of both epitopes in rabbits and in sera from patients with autoimmune diseases.

Methods

Peptides 147–154aa of La/SSB and 139–146aa of MBP were used for immunizations of New Zealand White rabbits. Spreading to the other epitopes of La/SSB (289–308aa, 349–364aa) as well as the recombinant human MBP (hMBP) and La/SSB (recLa) was identified using ELISA assays. Sera from 49 patients with systemic lupus erythematosus (SLE), 44 patients with Sjögren's syndrome (pSS), and 18 with rheumatoid arthritis (RA) with anti-Ro\La reactivity were tested against the two peptides and the hMBP.

Results

Rabbits immunized with the La epitope developed early antibodies against all three La/SSB peptides, hMBP, and recLa. In contrast, rabbits immunized with the MBP peptide developed a late immune response to other La epitopes, hMBP, and recLa. Inhibition experiments using the MBP peptide as inhibitor against the hMBP showed that the 79% of reactivity was abolished, indicating that this peptide is the major antibody target in MBP. Twenty percent of pSS, 27% of SLE, and none from RA patients reacted with the 147–154aa La epitope; 28% of pSS, 22% of SLE, and 17% of RA sera reacted with the MBP peptide. Finally, 17% of pSS, 37% of SLE, and 30% of RA sera reacted with the hMBP.

Conclusion

La 147–154aa peptide when used for animal immunizations can induce immediate epitope spreading while the mimicking epitope MBP 139–146aa induces a delayed response against the other La epitopes. A significant proportion of human sera reacted with both peptides and hMBP. Thus, despite the fact that these two peptides present molecular similarity, they induce different immune responses.

Authors’ Affiliations

(1)
Department of Pathophysiology, School of Medicine, University of Athens

Copyright

© The Author(s) 2003

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