Figure 1. Isolation of naive, marginal zone, memory and double-negative B cell subsets.

Human peripheral blood and splenic CD19⁺ B cells were stained with CD38 and CD24 to exclude transitional, germinal center, and plasma cells. The four gated populations were sorted according to CD27 and IgD expression: CD27⁺IgD⁻ memory cells (Mem), CD27⁺IgD⁺ marginal zone B cells (MZ), CD27⁻IgD⁺ naive (N) and CD27⁻IgD⁻ double-negative (DN) B cells. The profile shown corresponds to a spleen sample.