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Figure S1. Immunohistochemical analysis of Ig-secreting B-1 cells. Representative photographs for immunohistochemical analysis for cytoplasmic Ig⁺CD19^+/+prdm1^Flox/Flox B-1 (A), CD19^Cre/+prdm1^Flox/Flox B-1 (B), and 4-d LPS-treated B-2 splenocyte (C) cell culture from two independent experiments. Total cells per field were determined by phase contrast. Bar, 50 µm.