After activation and antibody staining, cells were washed in cold 0.04% BSA in PBS -/-. Single cells were encapsulated in Gel-Beads-in-Emulsion (GEMs) using the 10X Chromium X with a Chromium Next GEM Single Cell 5' HT Kit. https://cdn.10xgenomics.com/image/upload/v1673041195/support-documents/CG000424_ChromiumNextGEMSingleCell5_HTv2_CellSurfaceProtein_UserGuide_RevD.pdf Library prep was performed according to the manufacturer's protocol (CG000424 Rev D) 10X Genomics 5' HT v2 with Feature Barcode Technology for Cell Surface Proteins.