Plasma cell and memory B cell differentiation from the germinal center

- Only high-affinity GC B cells undergo PC differentiation.
- PC differentiation initiates in the light zone via antigen contact.
- Maturing PCs requires T-cell help and egress through the DZ.
- MBC differentiation is predominantly restricted to low affinity GC B cells.
- MBC differentiation also initiates in the light zone.

Germinal centers (GCs) form in secondary lymphoid tissues in response to antigenic challenge and are the site of somatic hypermutation, generating GC B cells with increasing affinity for the inciting agent that are positively selected over time. However, it is not until GC B cells differentiate into memory B cells and plasma cells and egress from the GC back into the circulation that effective long-lived humoral immunity is conferred upon the host. Here we review what is known about the signals that initiate the transition from a GC B cell into the memory B cell and plasma cell compartments and the downstream transcriptional regulation of these processes.