Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE credits
Rheumatoid Arthritis (RA) is a chronic inflammatory autoimmune disorder characterised by joint inflammation, bone erosion, and synovial tissue damage. Seropositive RA can be predicted several years before its onset by testing for anti-citrullinated protein antibodies (ACPA) in the blood serum. Despite being a biomarker, the role of ACPA in the disease progression remains unclear.
ACPAs are multireactive monoclonal antibodies that target the autoantigens modified by the enzyme peptidyl arginine deaminase (PAD). ACPAs are associated with proinflammatory effects in RA. An immunomodulatory effect of ACPAs may be linked to their glycosylation profile.
Antibodies are glycoproteins and possess N-linked glycans in the Fc region, which largely influence antibody binding to Fcγ receptors and effector functions, while the Fab glycans play a role in antigen binding. Sialic acid or galactose residues in antibody glycans can modulate FcγR interactions or activate lectin pathways, leading to engagement of anti-inflammatory receptors on immune cells. This underscores the need for further evaluation of ACPA properties, specifically how glycosylation patterns contribute to anti-inflammatory effects.
In this project, we aim to understand how the different glycosylation patterns on ACPAs modulate their potential to elicit a disease-modifying effect with the help of an in vitro immune complex assay and an in vivo arthritis model (CAIA, collagen antibody-induced arthritis) using an ACPA clone previously isolated from a B cell in the synovial joint of an RA patient. In addition to using the recombinant ACPA clone, we have also produced and compared different glycovariants of the antibody.
However, the in vitro assay was not continued further because ACPAs had very little influence on binding to immune cells. The in vivo model demonstrated variable levels of arthritis modulation among the different ACPA glycovariants. Notably, the immunomodulatory effect did not correlate with the sialic acid levels.
Keywords: ACPAs, Glycosylation, sialic acid, CAIA models
2026.