Splenectomy
Splenectomy was performed 15 days before DSS-induced colitis. Mice were fasted for eight hours before surgery. Then mice were anesthetized by intraperitoneal injection of pentobarbital 50 mg/kg. The spleen was removed after abdominal surgery and ligation of blood vessels. After the surgical intervention, mice were monitored daily to examine their health state. We reconfirmed the absence of spleen when the specimens were retained.