Mouse spleen single-cell suspensions and human PBMCs were fluorescently-labeled as previously described (14 (link)). Antibody staining panels used for experiments are available upon request from the corresponding author. Cell viability was determined using live/dead AQUA (Invitrogen). Samples were acquired on a CyAn ADP LX (Beckman Coulter) or sorted with a FACSVantage SE Turbo Sort DIVA v5.0 (Becton Dickinson) and analyzed using FlowJo software version 9.3.3 (Treestar).