Isolation of mononuclear cells from gastrointestinal tissue
Endoscopically obtained pinch biopsies were collected from Cohort 1 patients into Roswell Park Memorial Institute (RPMI) media containing penicillin and streptomycin and 10% foetal calf serum. Biopsies underwent enzymatic and mechanical digestion by being transferred into 5mL of warmed RPMI with penicillin and streptomycin/10% foetal calf serum with 1mg/mL Collagenase D (Sigma-Aldrich, St Louis, USA) and 100µg/mL DNAse I (ThermoFisher, Waltham, USA) and shaken at 37°C for 1h. Biopsies were then dissociated by vigorous agitation using a gentleMACS Dissociator (Miltenyi Biotech, Bergisch Gladbach, Germany) and strained through a 70µm strainer. Freshly isolated GMNC were analysed.