Session Information
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Background/Purpose: Sjögren’s syndrome (SS) is a rheumatic autoimmune disease characterized by focal lymphocytic infiltrations in the lacrimal and salivary glands, autoantibodies to the ubiquitous Ro and La nuclear antigens, severe dry mouth and eyes, arthritis, fatigue, pain and debilitation. In this project we used human proteome arrays to identify potential non-Ro/non-La autoantigens targeted by salivary gland plasmablasts from SS patients.
Methods: Recombinant human monoclonal antibodies (mAbs) derived from minor salivary gland plasmablasts of five individuals meeting the 2016 ACR/EULAR classification criteria for primary Sjögren’s syndrome were tested for binding to human proteome microarrays containing >15,500 GST- and 6xhis-tagged recombinant human proteins representing >75% of the human proteome spotted in duplicate (HuProt 3.0 arrays, CDI Laboratories). Each of six arrays was probed with a mAb pool (5 to 10 mAbs/pool) derived from one or two subjects. As controls, separate arrays were probed with secondary antibody alone (AlexaFluor 647 Affinipure F(ab’)2 Goat Anti-Human IgG (H+L)) and pools of mAbs specific for rabies, anthrax, and S. pneumoniae vaccines. The foreground to background ratio (F/B) was calculated for each array spot then transformed to fit a normal distribution for analyses. Significant binding was defined as normalized F/B ratios ≥ 2.0 SD above the mean value across all arrays and lack of binding by secondary antibody alone. Literature connectivity (IRIDESCENT), interactome and pathways (Ingenuity) bioinformatics analyses were conducted to investigate relationships among the bound antigens.
Results: A total of 201 proteins were found to be significantly bound by salivary gland mAbs, including Ro60, La, and Ro52 antigens. These were bound by patient mAbs but not by irrelevant mAbs or secondary antibody alone. Furthermore, of 199 novel non-Ro/non-La antigens identified, 16 were shared between 2 or more subjects on at least 2 arrays. Bioinformatics analyses revealed literature connectivity to the terms “salivary gland” or “Sjögren’s syndrome” among many of the bound antigens. The interactome showed multiple connections between several of the novel antigens; however, the most significant pathway among the shared antigen interactome was the proteasome/ubiquitination pathway.
Conclusion: Sixteen novel, non-Ro/La antigens shared between two or more patients were identified as possible targets of autoantibodies in SS. Pathway analysis of the shared interactome supports immune targeting of the proteasome/ubiquitination pathway by SG plasmablasts in SS.
Funding: National Institutes of Health (1P50 AR060804) and Oklahoma Center for the Advancement of Science and Technology (HR 16-055-01)
To cite this abstract in AMA style:
Longobardi S, Lawrence C, Koelsch KA, Smith K, Georgescu C, Joachims ML, Radfar L, Rasmussen A, Sivils KL, Wren J, Scofield RH, Farris AD. Specificity of Salivary Gland-Derived Monoclonal Antibodies from Sjogren’s Syndrome Patients Using Human Proteome Arrays [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/specificity-of-salivary-gland-derived-monoclonal-antibodies-from-sjogrens-syndrome-patients-using-human-proteome-arrays/. Accessed .« Back to 2017 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/specificity-of-salivary-gland-derived-monoclonal-antibodies-from-sjogrens-syndrome-patients-using-human-proteome-arrays/