E-cadherin can regulate type 2 cytokine production by human skin ILC2. (A) ILC2s were isolated from the skin of patients with AD (n = 4) and healthy controls (n = 8), and expression of KLRG1 was analyzed by flow cytometry. Representative flow plots are shown on the right. Numbers indicate percentages of cells within the top right quadrant of gated populations. (B) ILC2s were stimulated with IL-33, IL-25, and TSLP, and levels of KLRG1 gene and protein expression were measured by RT-PCR and flow cytometry. Statistical comparisons are compared with the negative (no cytokine) control. Numbers on the flow cytometry plots indicate the proportion of gated cells that express KLRG1 (n = 4). (C) E-cadherin expression by keratinocytes after control (left) or filaggrin (right) shRNA knockdown (bars, 50 µm; n = 3). (D) Expression of RORA, AREG, IL-13, IL-5, GATA3, and IL-4 mRNA relative to GAPDH by ILC2 activated using PMA/I before and after culture with rhE-cadherin (recombinant human E-cadherin) for 24 h (n = 7), as measured by PCR. (E) Ki67 and live/dead staining of ILC2 incubated with PMA/ionomycin in the presence or absence of E-cadherin. Data are representative of three independent experiments. Numbers indicate percentages of cells within the indicated gates. (F) IL-5 and IL-13 concentration in supernatant from ILC2 activated with IL-25 and IL-33 and incubated in the presence or absence of rhE-cadherin (n = 3). *, P < 0.05; **, P < 0.01; ***, P < 0.001, unpaired Student’s t test (min and max in A; mean and SEM in B, D, and F).