Modulation of Neutrophilic Inflammation in Rheumatoid Arthritis by Autoantibody Glycosylation

Neutrophil-mediated responses can be elicited by autoantibodies produced during rheumatoid arthritis (RA), such as anti-citrullinated peptide antibodies (ACPA), which form immune complexes (ICs). Although the presence of ACPA is included in the criteria for diagnosing RA, ACPA-positive individuals may have RA, remain healthy or will develop RA. Certain glycosylation patterns on the Fc domain of immunoglobulin G (IgG) antibodies, including ACPAs, can change months prior to RA onset, correlating to increased pro-inflammatory responses and increased likelihood to develop RA. Furthermore, pregnancy or RA treatment are associated with lower RA pathology which correlate with changes in IgG glycosylation patterns. This project will investigate pro- and anti-inflammatory neutrophil functions in response to stimulation with ICs consisting of IgG containing 'healthy' or RA-typical glycosylation profiles based on the hypothesis that particular IgG glycosylation patterns are more pro-inflammatory, promoting enhanced pro-inflammatory (or reduced anti-inflammatory) neutrophil responses which may promote RA.
To test this hypothesis, this project will identify typical IgG glycosylation patterns of healthy individuals and those affected by autoimmune diseases (e.g., RA, lupus, multiple sclerosis) using existing literature and databases. Once the patterns are determined, cell lines will be engineered to express human IgGs with the determined glycosylation patterns and for the generation of 'healthy' and 'pro-inflammatory' ICs. Neutrophils isolated from healthy blood donors will be stimulated with these ICs, and pro-inflammatory and anti-inflammatory neutrophil responses will be analysed.