Shining a light on germinal center B cells.
The mechanisms of B cell selection in lymphoid tissues are poorly understood. In this issue, Victora et al. (2010) use imaging of photoactivatable green fluorescent protein to define the movements of B cells in germinal centers and provide evidence that antibody affinity maturation is driven by competition for T cell help. Copyright © 2010 Elsevier Inc. All rights reserved.DOI: 10.1016/j.cell.2010.10.036