Germinal center reaction: antigen affinity and presentation explain it all

The selection and expansion of B cells undergoing affinity maturation in the germinal center is a hallmark of humoral immunity. A recent paper in Nature provides new insights into the relationships between the affinity of the immunoglobulin receptor for antigen, the ability of B cells to present antigen to T cells, and the processes of selection, mutation, and clonal expansion in the germinal center.