Aim: To assess the differentiation and regulation of antigen specific Th17 cells in vitro.
Methods: Naive CD4(+) T cells from OVA-TCR-transgenic mice (OVA-TCR-Tg) were isolated and co-cultured with splenocytes from normal BALB/c mice under different culture conditions. The expression and production of IL-17 and other cytokines were assessed.
Results: OVA peptide alone mainly induced Th1 type responses. Addition of TGF-beta plus IL-6 induced Th17 response. Furthermore, addition of IL-23 to cell culture could promote the differentiation of Th17 cells. Blocking of IFN-gamma and IL-4 by neutralizing monoclonal antibodies enhanced the percentage of IL-17-producing cells. LPS could promote the production of Th1 cytokines but had no significant effect on IL-17 expression.
Conclusion: Antigen specific Th17 cells are distinct from antigen specific Th1 and Th2 cells. TGF-beta, IL-6 and IL-23 are the factors responsible for promoting the differentiation and development of Th17 subset, whereas IFN-gamma and IL-4 have inhibitory effects.