The role of interleukin-23 in stability of in vitro T helper-17 cells.

Interleukin (IL)-17-producing T helper (Th)-17 cells have recently been explained as a distinct population of CD4+ T cells which play an important role in immunity against infectious agents. Establishment of persistent phenotype of Th17 cells and recognition of lineage-deviating factors are of most attractive goals in modern researches in immunology. Although IL-6 and TGF-β are frequently used to differentiate naive T cells to Th17 phenotype in mouse models, the application of IL-23 and its importance in preventing cells from plasticity needs to be more investigated. Our main objective was to evaluate the role of IL-23 in Th17 to Th1 plasticity. In this research project, we generated in vitro Myelin oligodendrocyte glycoprotein (MOG)-specific Th17 cells in the presence of TGF-β, IL-6, IL-23 and peptide MOG35-55. Th17 development was confirmed by assessment of relevant transcription factors and secreted cytokines by flowcytometry and ELISA, respectively. Th17 to Th1 plasticity was monitored by consecutive samplings in different time points without any extra supplementation of IL-23. Cell culture supernatant was evaluated for Interferon (IFN)-γ secretion and cells were evaluated for intracellular expression of this cytokine. Our results showed that the employed method was relatively convenient in developing antigen-specific Th17 cells. We also showed that IL-23 deprivation which happens by prolongation of culture period, can convert IL-17 producing cells to IFN-γ secreting Th1 phenotype. IL-23 can be considered as a Th17 phenotype stabilizing factor for in-vitro developed lineages.