Background and Objectives Th17 cells represent a subset of T helper lymphocytes that produces several inflammatory cytokines, including interleukin-17A, -17F, -21, -22, and tumor necrosis factor. Increased Th17 cell differentiation and IL-17 production have been observed in rheumatoid arthritis (RA) and in several other autoimmune diseases. IL-17 contributes to development of inflammation and promotes osteoclast differentiation in RA. We have studied the differentiation of Th17 cells.
Materials and Methods CD4 positive T cells were negatively separated by magnetic method from peripheral blood mononuclear cells (PBMC) of healthy volunteers. The cells were treated for 5-10 days with anti-CD3 and anti-CD28 antibodies and with TGFβ (2.5ng/ml), IL-6 (25ng/ml) and IL-1 (10ng/ml) cytokines, furthermore with anti-IL-4 (10μg/ml) and anti-IFNγ (10μg/ml) blocking antibodies. The IL-17 and IL-22 production was measured by ELISPOT and ELISA, the RORγt expression was measured by real-time PCR and by Western blot methods, cell viability was monitored by Trypan blue staining and by Annexin V binding.
Results Anti-CD3/CD28 treatment increased the IL-17 production, but did not alter the RORγt expression. The anti-CD3/CD28, TGFβ, IL-6, and IL-1 induced RORγt expression was further increased by the anti-IL-4 and anti-IFNγ antibody treatment. Anti-CD3/CD28-induced IL-22 production was inhibited by TGFβ, IL-6, IL-1, anti-IL-4 and anti-IFNγ antibody treatment. The applied treatments did not change the viability of the cells.
Conclusion Our present results suggest that IL-17 and IL-22 production are differentially regulated during CD4 T cell activation and Th17 differentiation.