Figure 1

Schematic representation of B-cell differentiation and maturation states. Schematic representation of B-cell differentiation and maturation states with respect to expression of CD19 and CD20, CD22, CD40 and B-cell activating factor receptor (BAFF-R) as well as their functions as discussed in the main text. There is of course a variety of additional surface markers characterizing various subpopulations of B cells (for reviews see [4, 12]).