Single-cell suspensions of spleen and mesenteric LNs (mLNs) were prepared as previously described (Yeh et al., 2011 (link)) and resuspended in R10 medium (RPMI 1640 with 10% FCS, 2 mM l-glutamine, 100 IU/ml penicillin, 100 µg/ml streptomycin, 1× nonessential amino acids, 1 µM sodium pyruvate, and 50 µM β-mercaptoethanol). Large intestine lamina propria lymphocytes were isolated using the Lamina Propria Dissociation Kit (Miltenyi Biotec) according to the manufacturer’s instructions. Cells were then isolated by centrifugation over a Percoll gradient, washed, and resuspended in R10 media.