NKG2D regulates CD4+ T cell differentiationvia interaction with DCs
NKG2D genetically modified CD4+ T cells were co-cultured with the stimulating irradiated DCs to explore the regulation of NKG2D on CD4+ T cells via the interaction with DCs. Cytokines secreted by genetically modified CD4+ T cells were tested. The results are shown in Figure 4A. NKG2D induced the secretion of IL-12 and suppressed the production of IL-10 and transforming growth factor-beta (TGF-β) from LV-NKG2D CD4+ T cells and LV-siRNA CD4+ T cells of JIA patients (P<0.05). However, NKG2D significantly increased IL-12 production (P<0.05) and had no significant effects on production of IL-10 and TGF-β from CD4+ T cells of healthy controls (P>0.05). Next, we assessed the effects of genetic modification of NKG2D on the polarization of T cells. As shown in Figure 4B and 4C, LV-NKG2D modified CD4+ T cells had a significantly increased percentage of IFN-γ+CD4+ T cells (P<0.05), but significantly reduced populations of CD25+Foxp3+CD4+ T cells (P<0.01) and IL-4+CD4+ T cells (P<0.05) compared with the respective blank control in both JIA and healthy groups. Additionally, genetic modification of NKG2D resulted in an increase content of the IL-17+ CD4+T cell subgroup in LV-NKG2D CD4+ T cells and reduced numbers of IL-17+ CD4+ T cell subgroup in LV-siRNA CD4+ T cells in JIA patients (P<0.05). No significant influence on the IL-17+CD4+ T cell subset was evident in the healthy controls (P>0.05). Expressions of transcription factors was assessed (Figure 4D). NKG2D upregulated the expressions of RORc and T-bet (P<0.05), down-regulated the expressions of Foxp3 (P<0.05) and GATA3 (P<0.01) in CD4+ T cells of JIA patients, and increased the expression of T-bet (P<0.05). No statistically significant change in the expressions of RORc, Foxp3, and GATA3 was observed in CD4+ T cells of the healthy controls (P>0.05).