Fig. 4: Impact of SOCS1 mutations on T cell proliferation and on regulatory T cells.

a Proliferation of T-cell blasts from healthy controls (HC) and patients. Day-10 T-cell blasts were stimulated or not with IL-2 (100 IU/ml), or anti-CD3-coated beads for 4 days. Proliferation was determined from the level of dilution of the CellTrace Violet dye. The panel shows proliferation of all T cells (CD3⁺). Top: representative histograms showing cell divisions of T-cell blasts (red peak) from an HC and from patient B1. Peak in black: unstimulated cells. The data are quoted as the percentage of cells having undergone at least one division. Bottom: the percentage of dividing cells from HCs and patients (data pooled from n = 4 independent experiments including a total of four HC, five patients with IL-2 25UI/ml and eight patients with anti-CD3 or IL-2 100UI/ml). Two-tailed p values were determined in an unpaired t test (IL-2 25UI/ml p = 0.0433, IL2 100UI/ml p = 0.0038, NS, not significant). b Left: a representative flow cytometry analysis of FoxP3 and CD25 markers in CD4+ T cells from an HC and from patient B1. Right: FoxP3⁺CD25⁺ CD4⁺ T cells (as a percentage of total CD4⁺ T cells) in the peripheral blood of HCs (n = 10) and patients (n = 5). c Naïve CD45RA⁺CD4⁺ T cells (as a percentage of total CD4⁺ T cells) in the peripheral blood of HCs (n = 10) and patients (n = 5). d Top: representative histograms of FoxP3 and Helios expression in CD4⁺CD25⁺CD127^low T cells from an HC (black) and patient B1 (red). Bottom: mean fluorescence intensity (MFI) of the respective T_reg cell markers in HCs (n = 10) and patients (n = 5). b–d Two-tailed p values were determined in a Mann–Whitney test (Panel B p = 0.0047; Panel D FoxP3 p = 0.008, Helios p = 0.0007, NS, not significant). a–d Data indicate mean with SD, and each dot corresponds to an individual. e Suppressive activity of regulatory T cells. VioBlue-labeled T_eff cells were cultured in the absence or presence of T_reg cells from HCs and patients (A2, D1, and E1). Proliferation was determined from the level of dilution of the VioBlue dye. Graphs indicate percentages of suppression from patients. Data are from three independent experiments in duplicate with a healthy control and indicated patient tested in pairs. Data indicate mean with SD of technical replicates due to the lack of cells for more experiments. Two-tailed p value was determined in a paired t-test between patients and controls (p = 0.0055). a–e *P ≤ 0.05; **P ≤ 0.01, ***P ≤ 0.001.