Figure 2.

B-cell development is arrested at the pre-B stage in IRF-4,8^-/- mice. (A) Bone marrow cells were analyzed for expression of B220, CD43, BP-1, and HSA using four-color FACS. The BP-1 and HSA profiles were obtained after gating on B220⁺, CD43⁺ cells. (B) Bone marrow cells were analyzed for CD19 and CD43 expression after gating on B220⁺ lymphocytes. (C) Intracellular μ expression in CD19⁺ CD43⁺, or CD19⁺ CD43^- IRF-4,8^-/- mutant B-lineage cells. Myeloid-lineage-depleted cells (Mac-1^-, Gr-1^-) from IRF-4,8^-/- bone marrow were stained with anti-CD19 and anti-CD43 antibodies. After fixation and permeabilization, the cells were reacted with an anti-IgM antibody (solid line) or an isotype control (broken line), and then analyzed by FACS.