Presentation Number: 792
Purpose: Human cartilage glycoprotein 39 (HCgp39) and type II collagen (cII) are suspected to be important arthritogenic antigens in patients with rheumatoid arthritis (RA). The majority of RA patients express MHC Class II alleles containing the shared epitope, including HLA DRB0401 (DR4). Recent findings suggest that a distinct subset of CD4+ T cells that produce interleukin 17 are the most important effector cell population mediating joint inflammation during experimentally-induced arthritis in mice. The study hypothesis is that presentation of HCgp39 or cII epitopes on human DR4 in the context of an inflammatory response will induce the formation or activation of antigen-specific, IL-17 producing CD4+ T cells in vivo. Methods: Human DR4 transgenic mice were immunized with HCgp39 or cII emulsified in either Incomplete (IFA) or Complete Freund’s adjuvant (CFA) and characterized for HCgp39 or cII-specific, ThIL-17 responses. Chicken type II collagen was purchased and the HCgp39 protein was produced in our lab by purification of MG-63 osteosarcoma cell supernatants over a heparin affinity column. Results: cII/CFA immunized mice have measurable increases in serum IL-17 compared to cII/IFA immunized and unimmunized mice. Secondary immunization with cII/IFA causes a decrease in serum IL-17 levels in the previously CFA/HCgp39 immunized mice. Restimulation of splenocytes from cII/CFA immunized mice led to higher in vitro IL-17 production than cII/IFA immunized mice, although all cultures were responsive to the addition of IL-23. Immunization with HCgp39/CFA led to measurable increases in serum IL-17 and anti-HCgp39 antibodies. Splenic B220+ cells from immunized DR4 mice were able to present cII and HCgp39 derived peptides to antigen-specific T cell hybridoma cell lines. Conclusions: These animal model systems will be valuable to study the development of ThIL-17 responses toward arthritogenic antigens.
S.K. Lundy, None.