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Affinity Purification and Comparative Biosensor Analysis of Citrulline-Peptide-Specific Antibodies in Rheumatoid Arthritis

Department of Immunology, Eötvös Loránd University, 1117 Budapest, Hungary
MTA-ELTE Research Group of Peptide Chemistry, Hungarian Academy of Science, Eötvös Loránd University, 1117 Budapest, Hungary
Laboratory of Interfaces and Nanostructures, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary
Department of Rheumatology, 3rd Department of Internal Medicine, Semmelweis University, 1125 Budapest, Hungary
Rheumatology, Buda Hospital of the Hospitaller Order of St. John of God, 1023 Budapest, Hungary
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2018, 19(1), 326;
Received: 30 December 2017 / Revised: 15 January 2018 / Accepted: 17 January 2018 / Published: 22 January 2018
(This article belongs to the Special Issue Musculoskeletal Diseases Therapy)
PDF [4391 KB, uploaded 24 January 2018]


Background: In rheumatoid arthritis (RA), anti-citrullinated protein/peptide antibodies (ACPAs) are responsible for disease onset and progression, however, our knowledge is limited on ligand binding affinities of autoantibodies with different citrulline-peptide specificity. Methods: Citrulline-peptide-specific ACPA IgGs were affinity purified and tested by ELISA. Binding affinities of ACPA IgGs and serum antibodies were compared by surface plasmon resonance (SPR) analysis. Bifunctional nanoparticles harboring a multi-epitope citrulline-peptide and a complement-activating peptide were used to induce selective depletion of ACPA-producing B cells. Results: KD values of affinity-purified ACPA IgGs varied between 10−6 and 10−8 M and inversely correlated with disease activity. Based on their cross-reaction with citrulline-peptides, we designed a novel multi-epitope peptide, containing Cit-Gly and Ala-Cit motifs in two–two copies, separated with a short, neutral spacer. This peptide detected antibodies in RA sera with 66% sensitivity and 98% specificity in ELISA and was recognized by 90% of RA sera, while none of the healthy samples in SPR. When coupled to nanoparticles, the multi-epitope peptide specifically targeted and depleted ACPA-producing B cells ex vivo. Conclusions: The unique multi-epitope peptide designed based on ACPA cross-reactivity might be suitable to develop better diagnostics and novel therapies for RA. View Full-Text
Keywords: rheumatoid arthritis; citrulline-peptides; autoantibody; affinity; cross-reaction; targeting rheumatoid arthritis; citrulline-peptides; autoantibody; affinity; cross-reaction; targeting

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Szarka, E.; Aradi, P.; Huber, K.; Pozsgay, J.; Végh, L.; Magyar, A.; Gyulai, G.; Nagy, G.; Rojkovich, B.; Kiss, É.; Hudecz, F.; Sármay, G. Affinity Purification and Comparative Biosensor Analysis of Citrulline-Peptide-Specific Antibodies in Rheumatoid Arthritis. Int. J. Mol. Sci. 2018, 19, 326.

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