Figure 5

IFN-α/IFNAR signaling induced expression of NKG2DLs on Treg cells. (A) Frequencies of Mult-1 expression on Treg cells stimulated by B6.MRL/lpr mouse serum, in the presence or absence of indicated antibodies, were analyzed. (B) Frequencies of Mult-1 expression on Treg cells stimulated in the presence or absence recombinant murine IFN-α (1000 U/mL) were analyzed. B6.MRL/lpr mouse serum were used as positive controls. (C) The levels of serum IFN-α were measured by ELISA for 30 HCs, 36 mild/moderate SLE patients and 26 severe SLE patients. (D) FCM assay results for the frequency of Treg cells from representative mild/moderate SLE patients and severe SLE patients. The gated Treg cells were further investigated for IFNAR1/R2 expression. The representative FCM assay (left) of expression of IFNAR on Treg cells are shown as indicated (black solid line). Filled gray histograms represent the staining with control Abs. Bar graphs (right) present the statistical results of the IFNAR⁺ Treg cells ratio for Treg cells isolated from 30 HCs, 36 mild/moderate SLE patients and 26 severe SLE patients. (E) Frequencies of expression of ULBPs on Treg cells stimulated by serum from SLE patients with different disease activity (n = 25), in the presence or absence of anti-IFNAR2 mAb (5 μg/mL), were analyzed. (F) Cytolysis percentage and (G) Treg cells count in the co-culture system with NKG2D⁺CD4⁺ T cells and IFN-α stimulated Treg cells at different ratios of effector:target cells, with or without the neutralized antibodies, measured by the ⁵¹Cr-release assay and apoptosis assay, respectively. All values represent the mean ± SD of three independent experiments. ^** P < 0.01, ^*** P < 0.001.