2.7. Enzyme‐linked immunosorbent assay

Interleukin‐17A, IFN‐γ and TNF‐α expression levels in the intestine were determined by ELISA. Briefly, intestinal tissue was homogenized in 1 mL of normal saline with protease inhibitors (Sigma‐Aldrich). Then, the homogenates were centrifuged at 1000 g at 4°C for 30 minutes, and the supernatant was stored at −80°C until analysis. Interleukin‐17A, IFN‐γ and TNF‐α levels (pg/mg) were measured by ELISA (eBioscience, San Diego, CA).