Cells were isolated from spleens and pancreata as previously described (36 (link)). Lymph nodes were macerated in HBSS (Invitrogen Life Technologies) + 10% FBS (HyClone). Cells were subsequently stained for flow cytometry analysis using the following reagents and reactive antibodies: 7-aminoactinomycin D (7-AAD), B220 (6B2), BCL-6 (K112–91), CCR6 (140706), CD11b (M1/70), CD11c (HL3), CD4 (RM4–5), CD44 (IM7), CD69 (H1.2F3), CD95/FAS (JO2), CD278/ICOS (C398.4A), CXCR3 (CXCR3–173), CXCR5 (2G8), eFluor Fixable Viability Dye, GL7, IgD (11–26c), IgMa (DS-1), IgMb (AF6–78), IgM (μ chain specific), NKG2D (cx5), or PD-1 (J43) (BD Biosciences, eBioscience, ThermoFisher Scientific, or Tonbo Biosciences). Biotinylated human insulin (Sigma-Aldrich) (33 (link)) was used to detect insulin-binding specificity. Avidin-fluorochrome conjugates were used to detect biotinylated reagents. Samples were acquired using a BD Biosciences LSR II flow cytometer and data were analyzed using FlowJo software (Tree Star, Inc).