ARG1 and cystic fibrosis: We showed here that instillation of “sterile” agarose beads in a rat biofilm model, extensively used in the field of cystic fibrosis research, activates the same Th2 cytokines (IL-5 and IL-13) and Th2 innate cells (eosinophils and Arg1+ M2 macrophages) as observed in human CF patients (Moser et al., 2000; Grasemann et al., 2005; Murphy et al., 2010; Tiringer et al., 2013).