Peripheral blood was obtained by intra-cardiac puncture and collected in EDTA microtainers (BD Biosciences, CA, USA). Bone marrow cells were harvested by flushing single femur and tibia with ice cold PBS containing 2% fetal bovine serum (FBS, Thermo Fisher Scientific, MA, USA). Total and differential cell count was determined using a Hemavet hematology analyzer with veterinary software (Drew Scientific Inc., CT, USA).
Lamina propria cells were isolated and analyzed by flow cytometry as previously described 44 (link) and in supplementary methods. Apoptosis of cecal tissue neutrophils was enumerated using Annexin V/7AAD-apoptosis assay kit (BD biosciences, CA, USA) as per manufacturer's instructions. Flow cytometry of apoptosis assay was performed on a BD FACS Acuri™ C6 flow cytometer equipped with CFlow® Plus (BD Biosciences, CA, USA) software and analyzed using FlowJo V.10 (Tree Star, OR, USA).