Variation of Cell Activity in NKT1- and NKT2-like cells induced by Atmospheric Pressure Oxygen Plasma

Atmospheric pressure oxygen plasma irradiation of NKT-like cells demonstrated that the activities of NKT1 and NKT2 cells can be modulated. The oxygen plasma was applied to NKT-like EL-4 cells using a torch-type dielectric barrier discharge plasma source. The per-cell cytokine production (IFN-γ, TNF-α, IL-4) and expression levels of the transcription factors T-bet, GATA3, and PLZF were evaluated following plasma irradiation. The product of gaseous ozone concentration and plasma irradiation time (ozone CT value) was used as the plasma dose parameter. At a CT value of 16, marked increases in T-bet expression and IFN-γ/TNF-α production were observed, whereas GATA3 and IL-4 remained minimally affected, indicating preferential activation of NKT1 cells. By contrast, at a CT value of 133, elevations in GATA3, PLZF, IFN-γ, TNF-α, and IL-4 production were detected, indicating concomitant activation of NKT1 and NKT2 cells. Collectively, these findings suggest that atmospheric pressure oxygen plasma irradiation, defined by the ozone CT value, enables biphasic and subset-selective modulation of NKT1 and NKT2 cell activity.