Non-FcεR bearing mast cells secrete sufficient interleukin-4 to control Francisella tularensis replication within macrophages

► We utilize P815 mast cells and J774 macrophages as surrogates for primary mast cells and macrophages respectively. ► Mast cell activation by non-FcεR driven signals produces IL-4 and control intramacrophage LVS replication. ► Inhibition in vitro is preserved at ratios relevant to cellular infiltration following pulmonary challenge.