Figure 2.

BAFFR, TACI, and BCMA are expressed at different stages of B cell development. After exiting the bone marrow, B cell precursors (pre-B cells) differentiate into immature transitional B cells that have anti-inflammatory functions. Transitional B cells then give rise to mature naïve and mature anti-inflammatory B cell subsets. Mature naïve B cells can become activated and further differentiate into short-lived plasma cells, memory B cells, and plasmablasts, which finally become long-lived plasma cells. All three BAFF and APRIL receptors are expressed at various levels on B cell subsets. BAFFR is highly expressed from the transitional B cells to the mature naïve B-cell stage. TACI is highly expressed from the mature naïve B cells to the activated and memory B cell stages. BCMA is most highly expressed by plasmablasts and short- and long-lived plasma cells.