Do Memory B Cells Form Secondary Germinal Centers? It Depends.

The memory B-cell pool in an immune individual is more heterogeneous than previously recognized. The different types of memory B cells likely play distinct roles in tuning the secondary immune response because they differ in their potential to generate plasmablasts, which secrete antibodies, or germinal center (GC) cells, which generate new and higher affinity memory cells. We propose that the production of plasmablasts or GC cells by a memory B cell is controlled by its state of differentiation and the amount and affinity of antigen-specific antibodies present in the individual in which it resides.