Quantification of tight junction gene expression ( Tjp-1 , Cldn1 , Ocln ) by qPCR in murine AEC IAV-infected and treated with rPlet (20 ng/ml) with/without Src activator (10 µM). Results are shown as fold change over IAV-infected AEC without rPlet1 ( n = 4) ( Tjp-1 **** p < 0.0001; Cldn1 **** p < 0.0001; Ocln ** p = 0.0024). Data are representative of three independent experiments showing mean ± SEM calculated using one-way ANOVA and Tukey’s post-hoc tests. j represents a single experiment performed with 3 (mouse) or 4 (human) different biological independent samples showing mean ± SEM and results were analyzed by two-way ANOVA and Tukey’s post-hoc test. BMDM bone marrow-derived macrophage, AEC alveolar epithelial cell, BALO bronchoalveolar lung organoid, TER transepithelial resistance, TR-AM tissue-resident alveolar macrophage, D day, inh inhibitor. Source data are provided as a Source Data file.