Bone marrow-derived mast cells +- IL-33 48h

Mast cells are tissue resident granulocytes which are most abundant at the interface between tissues and the external environment, such as around blood vessels, in the skin or mucosal surfaces in the lungs and gut. Pathologically they are involved in allergic reactions and anaphylaxis, however they may also play protective roles in responses to some infections, particularly to pathogenic helminths. Mast cells also express high levels of the IL-33 receptor, which like TLRs, activates Myd88 dependent signalling pathways to drive de novo cytokine production in mast cells.IL-33 is a member of the IL-1 family known to stimulate a number of immune cell types including mast cells. IL-33 is a strong activator of de novo cytokine production in mast cells without inducing degranulation, although it has also been shown to synergise with other signals to promote degranulation. Bone Marrow-Derived Mast cells (BMMCs) were cultured as described previously [27]. Briefly, bone marrow was flushed in PBS and the cells pelleted by centrifugation. Cells were cultured at 1 million cells per ml in RPMI 1640 supplemented with 10% FBS (Biosera/Labtech), 5 mM l‐Glutamine (GIBCO Life Technologies), 100 U/ml Penicillin (GIBCO Life Technologies), 100 μg/ml Streptomycin (GIBCO Life Technologies), 25 mM HEPES (Lonza), 1 mM sodium pyruvate (Lonza), 1X nonessential amino acids (Lonza), 50 μM 2‐mercaptoethanol and 30 ng/ml IL‐3 (PeproTech). Cells were passaged twice per week and used between passage 12 and 16. 4 independent BMMC cultures were either stimulated with 10 ng/ml IL-33 for 48 hours or left unstimulated, followed by single shot LC-MS analysis.