[Regulation of antigen specific Th17 cells differentiation in experimental autoimmune uveitis].

OBJECTIVE

To assess the regulation of antigen specific Th17 cells differentiation in experimental autoimmune uveitis (EAU).

METHODS

A randomized controlled trials research. EAU model was made through subcutaneous injection of interphotoreceptor retinoid-binding protein (IRBP) at backs and bellies. Mouse splenic CD4 T cells were collected on the fourteenth day and cultured in vitro in the cell culture plates containing IRBP antigen for 72 hours under different conditions: control group, TGF-beta group, IL-6 group, IL-23 group, TGF-beta + IL-6 group, TGF-beta + IL-6 + IL-23 group, IL-27 group, all transretinoic acid (ATRA) group. Cells and the clear liquid were collected. Then Th17 cells, IL-17 and other cells, cytokines were assessed by flow cytometry and ELISA. All data were analyzed by Student's t test.

RESULTS

Flow cytometric detection and ELISA experimental results showed:IRBP polypeptide alone mainly induced Th17 and Th1 response. Addition of TGF-beta and IL-6 induced the differentiation of antigen specific Th17 cells. Percentage of Th17 cells increased from 7.55% to 13.08% (t = -2.842, P = 0.048), and the concentration of IL-17 in cell culture fluid increased from 50.66 microg/L to 164.12 microg/L (t = -9.493, P = 0.009). Percentage of Th1 cells reduced from 6.33% to 3.43% (t = 6.059, P = 0.004). Percentage of Treg cells reduced from 4.96% to 1.52% (t = 5.683, P = 0.005); Furthermore, addition of IL-23 could enhance Th17 cells differentiation induced by TGF-beta and IL-6. Compared with IRBP polypeptide alone group, percentage of Th17 cells increased from 7.55% to 18.37% (t = -3.329, P = 0.029), and percentage of Th1 and Th2 cells reduced obviously (t = 7.410, P = 0.002; t = -3.863, P = 0.018). While IL-27 suppressed the differentiation of Th17 cells. Percentage of Th17 cells reduced from 7.55% to 1.92% (t = 4.425, P = 0.041), while percentage of Treg cells increased from 4.96% to 9.98% (t = -5.073, P = 0.015); In ATRA group, percentage of Th17 cells reduced from 7.55% to 4.06% (t = 2.163, P = 0.099).

CONCLUSIONS

Antigen specific Th17 differentiation is distinct from 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 IL-27 has inhibitory effects.