library_construction_protocol: Spleens were crushed and filtered with a 70µM mesh strainer. Harvested splenic B-cells were enriched by CD43, Ter119 and CD4 negative selection using MACS LS Columns (Miltenyi Biotec). Single-cell suspensions were stained with antibodies and sorted by flow cytometry. Libraries were prepared with Chromium Single Cell 5' Reagent Kit v.2 (10x Genomics) following the manufacturer's protocols.