Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
Citrullination of Mouse Collagen Breaks Tolerance and Induces an Inflammatory Arthritis in the Absence of Adjuvant.
P. Lacy, Jordan, J. Duryee, Michael, D. Hunter, Carlos, R. O'Dell, James, R. Mikuls, Ted, M. Thiele, Geoffrey, W. Klassen, Lynell
Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease that primarily affects the synovial joints. Anti-citrullinated protein antibodies (ACPA) are predictive markers of the disease and its severity. Previous studies have demonstrated that ACPA can be induced in mice following injection of citrullinated type II collagen (Cit-Coll) in the presence of Freund's complete adjuvant (FCA). Therefore, it was the purpose of this study to determine whether mouse Cit-Coll in the absence of adjuvant can break tolerance and initiate an inflammatory arthritis in DBA/1 mice.
Mouse type II collagen was citullinated using peptidyl arginine deiminase (PAD) and injected into DBA/1 mice at a concentration of (100 mg) in the base of the tail weekly for 5 weeks. Control groups were immunized with PBS, collagen, and collagen FCA. Animals were evaluated weekly for inflammation of the joints and serum was collected for the presence of anti-collagen or modified collagen antibodies. At week 6, animals were sacrificed paws removed for histology and spleens collected. The CD3+ T cells were then isolated and proliferated against collagen, albumin, Cit-Coll or Cit-albumin. Supernatants from the proliferation assays were collected and assayed for the presence of cytokines.
Following 6 weeks of immunization, a significant increase in inflammation was observed as assessed by paw thickness and scoring in the Cit-Coll mice compared to controls. An increase in serum antibodies to Cit-Coll and Cit-albumin was present. However, no significant increase in antibodies to collagen was observed. In contrast, the immune response to Cit-Coll was predominantly T cell as shown by the increase in proliferative response to collagen and Cit-Coll. Assessment of cytokines from the proliferation supernatants reveled increases in IL-6 and IL-23 following from Cit-Coll immunized mice. Finally, histological analysis of joints from these animals showed an increase in joint erosion an inflammation in the Cit-Coll immunized mice.
These data support the observation that citrullination of proteins increases the risk of this erosive inflammatory disease. Also, that citrullinated mouse type II collagen immunized in the absence of adjuvant causes an increase in T-cell proliferation with minimal antibody response to native collagen. The T-cell cytokine responses generated an IL-6 and IL-23 profile indicating an autoimmune response. Also, joint erosion and inflammation is evident in the Cit-Coll immunized mice as determined by scoring, paw thickness, and histology. Thus, this report suggests that citrullinated self-proteins may result in the abrogation of tolerance and the induction of an autoimmune response.
To cite this abstract, please use the following information:
P. Lacy, Jordan, J. Duryee, Michael, D. Hunter, Carlos, R. O'Dell, James, R. Mikuls, Ted, M. Thiele, Geoffrey, et al; Citrullination of Mouse Collagen Breaks Tolerance and Induces an Inflammatory Arthritis in the Absence of Adjuvant. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :2235