Date: Sunday, October 21, 2018
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Autoantibodies against citrullinated proteins are found in 64-89% of rheumatoid arthritis (RA) patients, with a specificity of 88-99%. While citrullinated vimentin, fibrin and histone have been implicated as targets of autoantibody reactivity, new targets, such as as Tenascin-C, continue to be uncovered. To this end, we performed an unbiased epitope-level characterization of autoantibodies from RA serum samples using a high density peptide microarray.
Our high-density peptide array, comprised of over 4.6M peptides, contains the entire annotated human proteome from the UNIPROT database. The 20,188 unique proteins were represented as overlapping 16-mer peptides. In addition to native peptide sequences, sequences containing arginine residues were replaced with citrulline and lysine residues were replaced with homo-citrulline to provide a comprehensive screen against all possible epitopes. We analyzed IgG antibodies for 27 serum samples (9 control, 9 RA DMARDS responders and 9 RA DMARDS non-responders).
Autoantibody reactivity was seen ubiquitously in all RA serum samples, with citrullinated peptides being the most prevalent over homocitrullinated and native peptide sequences. Hierarchal clustering revealed strong autoantibody reactivity against citrullinated peptides in almost all (8/9) RA DMARDS non-responder and 4/9 RA DMARDS responder samples. Within this group of RA samples with high reactivity, identical immunodominant epitopes were observed in 959 proteins. Within the 959 proteins, which included previously known targets such as vimentin, fibrin and type II collagen, over half have not been previously associated with RA. These include proteins such as PATE4 and NENF.
Using high-density peptide arrays, antibody reactivity was observed against citrullinated proteins that have not been previously associated with RA. These protein targets may further contribute to our understanding of the role of autoantibodies in RA pathophysiology.
To cite this abstract in AMA style:Lo K, Li H, Sullivan E, Patel J. Comprehensive Antibody Profiling Using High Density Peptide Arrays Reveals Novel Citrullinated Protein Targets in Rheumatoid Arthritis Serum Samples [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/comprehensive-antibody-profiling-using-high-density-peptide-arrays-reveals-novel-citrullinated-protein-targets-in-rheumatoid-arthritis-serum-samples/. Accessed September 29, 2022.
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