High Affinity Memory Cell Production in the Germinal Centers. How Far Can Selection Reach?

T-cell-dependent antigens can trigger B cells to differentiate into antibody-secreting plasma cells. Alternatively, following their activation by antigen, B cells may also differentiate into high-affinity memory cells. The two differentiation pathways are associated with different environments within the secondary lymphoid organs. Antibody-secreting plasma cells are produced in the B-cell foci that develop in the T-cell areas (1). In contrast, germinal centers (CG) are the site of memory formation. Here B cells undergo somatic mutation (2,3) and affinity-based selection (4,5,6). Memory cells generated as a result of these processes may be triggered into a fast, high-amplitude antibody response on re-encounter with their specific antigen. This is known as the secondary response.