Figure 3. Immunophenotyping of murine B cells.

B-lymphocyte subsets were immunophenotyped by multiparameter flow cytometry. A gating strategy that was used to identify some of the B-cell subpopulations is shown. (A) First, cellular area, height, and width measurements were obtained in a channel with linear scale to gate on singlets and exclude doublets. (B) Next, gates were set to include CD45⁺ leukocytes and exclude FSC^low cell debris out. (C) CD138 and B220 were used to gate on plasmablasts (CD138⁺B220^low/–), plasma cells (CD138⁺B220^–), and B cells (B220⁺). Panels D–F show the gating for (E) B220⁺CD1d⁺CD5⁻CD23⁻CD21⁺IgM⁺ marginal zone B cells, (E) B220⁺CD1d⁺CD5⁻CD23⁻CD21⁻IgM⁺ transitional 1 (T1) B cells, and (F) B220⁺CD1d⁺CD5⁻CD23⁺CD21⁺IgM⁺ T2 B cells. Panels G–I show gating for B1 B-cell populations, and the identification of (H) CD11b⁺CD23⁻B220^lo/−CD5⁻ B1b B cells and (I) CD11b⁺CD23⁻B220^lo/−CD5⁺ B1a B cells. Panels J and K show the identification of B220⁺CD138⁻CD95⁺GL7⁺ germinal center B cells. Panels L–O illustrate the gating for B220⁺CD19⁺CD5⁻GL7⁻CD23⁺CD21^lo/int naive follicular B cells. FSC = forward side scatter.