Mice were given 2 μg/g of anti-CD42b or the appropriate IgG control during the first day of the experiment. CBCs were obtained at 1.5 and 24 hours and lungs and BM were obtained at 24 hours to show that the lung Mks were specifically affected by the anti-CD42b (Supplemental Figures 12 and 13). On the following day the mice were given ST2-Fc (5 μg/mouse) (R&D Systems). On day 4 the mice were sacrificed. For the IL-33 depletion experiments, pups were given either ST2-Fc or IgG (200 ng/pup) subcutaneous injections within hours of birth and again on day 4. On day 7 the pups were sacrificed with 10 minutes of CO2 and then decapitation. After sacrificing mice for each experiment flow cytometry was used for data analysis.