Figure 2.

B cell gating strategy for determining CD38^lowCD21^low, transitional B cells (CD38^hiIgM^hi) and plasmablast (CD38^hiIgM^low) subpopulations. The first gate, R5, selects lymphocytes based on side-scatter versus forward-scatter. CD19 expression is used to select B cells (CD19⁺ cells) in the second gate, R6. The B cells (R6) are analysed further for CD21 and CD38 expression to identify gate 7, CD38^lowCD21^low cells. Alternatively, the B cells (R6) are analysed for immunoglobulin (Ig)M versus CD38 expression to identify gate 8, transitional B cells (CD38^hiIgM^hi) and gate 9, plasmablasts (CD38^hiIgM^low).