Effect of ROR γt on regulation of IFN-γ secretion of T cell subpopulations (90.15)

Abstract

Abstract It has been known that retinoid-related orphan receptor γt (RORγt) is a key transcription factor for development of IL-17 producing CD4 T cells (Th17), which are negatively regulated by interferon-γ (IFN-γ) produced by Th1 cells, however, whether the RORγt regulates IFN-γ production in T cell subsets has not been elucidated. In our study the peripheral blood mononuclear cells isolated from peripheral blood of healthy human donors were stimulated with CD3 mAB and cultured in IL-2 containing medium for 12 days. The activated T cells were transfected with three chemical synthesized small interfering RNA (siRNA) sequences for RORγt gene using liposomes. By using semi-quantity RT-PCR assay, the RORγt gene expression was inhibited in activated T cells that transfected with RORγt-siRNA-1026 and -1197, but was not inhibited in that with RORγt-siRNA-982. By using flowcytometry, the percentages of IFN-γ producing cells in total T cells, CD4+ T cells and CD8+ T cells that transfected with the sequence of RORγt-siRNA-1026, significantly decreased to 35.19, 32.78, and 41.84, respectively, in comparison of nontransfected group (43.39, 44.54, and 50.04, respectively) (p< 0.05). In conclusions, the transcription factor RORγt may also be involved in the positive regulation for IFN-γ production in human T cells, especially in CD4+ T cells.