Fig. 2: Elevated lysosomal acidity and CTSL activity promote eosinophil activation.

A–L Eosinophils were isolated from the peripheral blood of Il5 Tg mice and treated with or without IL33 (20 ng/ml) for 8 h. ELISA analysis (n = 3 biological replicates) of culture supernatants for IL4 and IL13, and flow cytometry analysis (n = 3 biological replicates) for CD69 and intercellular cell adhesion molecule-1 (ICAM-1) expression on eosinophils incubated with or without 100 nM Con. A (A–D), 50 µM E64D (E–H), and 50 µM SID26681509 (I–L). M–P Eosinophils were differentiated from bone marrow of sex-matched control and Ctsl ^eoΔ mice and treated with or without IL33 (20 ng/ml) for 8 h. ELISA analysis (n = 3 biological replicates) of culture supernatants for IL4 (M) and IL13 (N), and flow cytometry analysis (n = 3 biological replicates) for CD69 (O) and ICAM-1 (P) expression on eosinophils. Q–T Eosinophils were isolated from the peripheral blood of patients with asthma and treated with or without IL33 (100 ng/ml) for 8 h. ELISA analysis (n = 3 biological replicates) of culture supernatants from eosinophils incubated with or without 100 nM Con. A (Q and R), 50 µM SID26681509 (S and T) for IL4 and IL13. Data presented are representative of three independent experiments and shown as mean ± SEM. Statistical analyses were calculated using two-way ANOVA with Sidak’s multiple comparisons test.