Jagged 1 knockdown abrogates MSC protection in an OVA driven mouse model of allergic airway inflammation. Representative images of H & E staining (magnification x100 (left column) and x400 (right column)) from OVA sensitized mice at day 28. MSC, Jag 1 KD MSC or PBS was administered intravenously on day 7 and day 14 (A). A single cell suspension was isolated from the lung at day 19 and analysed by flow cytometry. CD4+ cells were gated and examined for FoxP3 expression (B), summarised as % positive CD4+FoxP3+ cells (C). Spleen cells isolated at day 19 were cultured and re-stimulated with 200 μg/ml OVA for 48 hours. Supernatant was collected and IL-10 expression determined by ELISA (D) n = 5. (*, P <0.05; **, P <0.01). KD, knockdown; MSC, mesenchymal stromal cells; OVA, ovalbumin.