Purification and in vitro culture of naive and germinal center B cells

Splenic naive B cells were purified by CD43 depletion (Miltenyi). GC B cells were purified as previously described (Luo et al., 2018 (link)). Naive and GC B cells were cultured in vitro in the presence of 10 µg/ml (anti-IgM + anti-IgG; Jackson ImmunoResearch) and/or 20 µg/ml anti-CD40 antibody (FGK45; Bio X Cell) with or without 25 ng/ml IL-4. For cell proliferation studies, naive B cells were stained with CellTrace Violet (Thermo Fisher) according to the manufacturer’s protocol. HEK293T cells were transiently transduced with a MIZ1-IRES-GFP expressing vector or GFP control (VectorBuilder) using Lipofectamine (Invitrogen). Cells were analyzed 48 h after transduction.