Fig. 6: IL33 expression selectively maps to Sca1^± thymic mesenchyme.

a Representative FACs plots illustrating the proportion of IL33^cit expressing CD45⁺ thymic cells and total CD45^- thymic stromal cells (blue histogram). Red histograms represent florescence levels in control WT mice. b Quantitation of IL33^cit expression in defined thymic stromal populations; cTEC (CD45^-EpCAM-1⁻UEA1⁻Ly51⁺), mTEC (CD45^-EpCAM-1⁻UEA1⁺Ly51⁻), mTEC^hi (CD45^-EpCAM-1⁻UEA1⁺Ly51⁻MHCII⁺CD80⁺), mTEC^lo(CD45^-EpCAM-1^-UEA1⁺Ly51⁻MHCII^-CD80⁻), Endothelium (TER119⁻CD45⁻EpCAM-1⁻CD31⁺), Mesenchyme (TER119⁻CD45⁻EpCAM-1⁻CD31⁻Integrinα7⁻), Pericytes (TER119⁻CD45⁻EpCAM-1⁻CD31⁻Integrinα7⁺), (where n = 7 animals for TEC subsets and n = 5 animals for all other subsets, obtained from 2 independent experiments). c Representative FACs plots showing Sca-1 expression in thymic mesenchyme, and IL33^cit expression within Sca-1⁺ and Sca-1⁻ subsets. Blue histograms are from IL33^cit mice, red histograms from control WT mice. d Total thymus cellularity, Sca-1⁺ mesenchyme numbers/proportions in WT mice following SLI exposure at indicated time points (n = 6 animals obtained from 2 independent experiments) with statistical analysis from a one-way ANOVA comparing means of each group to D0 with Dunnett’s multiple comparisons. e Comparative analysis of TEC (blue line) and Sca-1⁺ mesenchyme (red line) recovery at indicated time points in WT mice (n = 6 animals obtained from 2 independent experiments). f FACs plots showing IL4Rα expression in Sca-1⁺ mesenchyme from WT (blue histogram) mice, where against Il4ra^−/− mice (red histogram) were used for control staining levels. g Quantitation of Sca1⁺ mesenchyme in WT and Il4ra^−/− mice at steady state (D0) (WT n = 5 and Il4ra^−/− n = 6 animals obtained from 2 independent experiments), from a two-tailed unpaired Student’s t test. h Injection and irradiation regime of 5μg recombinant IL4-complexes/PBS into WT mice. Analysis of Sca-1⁺ mesenchyme was performed at day 7 and day 14 after injection regime, n = 6 minimum. i Numbers of Sca-1⁺ thymic mesenchyme cells at day 7 and day 14 post-SLI following PBS (D7 n = 6 and D14 n = 7 animals) or IL4c (D7 n = 7 and D14 n = 7 animals) injection, obtained from 2 independent experiments. Statistics from a two-tailed unpaired Student’s t test. All analysis was carried out across at least two independent experiments. All error bars show mean ± SEM.