Cd19 bv421 clone hib19

PBMCs were isolated using Lymphoprep (STEMCELL Technologies, Vancouver, Canada) and Leucosep tubes (Greiner Bio‐One, Kremsmünster, Austria) according to the manufacturer’s instructions and either used immediately or cryopreserved. PBMCs were stained with CD19 BV421 (clone HIB19; Biolegend, San Diego, CA, USA), CD27 APC (clone O323; Biolegend), CD20 FITC (clone 2H7; BD, Franklin Lakes, NJ, USA) and a dump channel mix containing CD3 PE‐Cy7 (clone UCHT1; eBioscience, Waltham, MA, USA), CD10 PE‐Cy7 (clone HI10a; BD) and CD14 PE‐Cy7 (clone M5E2; BD). Naive B‐cells, memory B‐cells, non‐B lymphocytes and monocytes were sorted with a FACSAria III sorter (BD Biosciences) with gating as shown in Figure 2a.

Peripheral blood mononuclear cells were thawed, and stained with a panel consisting of 7-AAD viability staining solution (eBioscience), CD14-BV421 (clone M5E2), CD19-BV421 (clone HIB19), CD16-FITC (clone 3G8), CD3-PE (clone SK7), CD4-BV711 (clone OKT4), and CD56-PE Cy7 (clone HCD56, all antibodies from Biolegend), and sorted for CD4 T cells (CD14^– CD19^– CD3⁺ CD4⁺) and NK cells (CD14^– CD19^– CD3^– CD56/CD16⁺) using a Sony SH800 sorter. Post-sorting, all cells were cultured in RPMI (Gibco), with 10% FBS (Thermo Fisher), 1% L-glutamine (Hyclone) and 1% penicillin/streptomycin/amphotericin (Thermo Fisher) (RP10). CD4 T cells were plated in RP10 with plate-bound anti-CD3 (clone OKT3, eBioscience), anti-CD28/CD49d (BD Biosciences) and PHA-L (eBioscience) for 48 h. NK cells were separately plated in RP10 with 300 IU/ml recombinant human IL-2 (R&D) for 72 h.