Apoptosis and antigen affinity limit effector cell differentiation of a single naïve B cell

For a single B cell, many roads to take To successfully fight a pathogen, immunological B cells must wage a multipronged attack: They can differentiate into antibody-secreting plasma cells or become T cell–helping germinal center cells, or even long-lived memory cells. But can a single B cell acquire all of these different fates? To find out, Taylor et al. tracked the responses of single B cells in mice. Although some B cells acquired only one fate, others differentiated into all three. The authors linked the ability of B cells to differentiate into multiple subsets to their ability to proliferate and resist cell death, and the affinity of their antigen receptor. Science , this issue p. 784