title: Shining a light on germinal center B cells.
abstract: 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.
authors.affiliation: Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, CA 94143, USA. jason.cyster@ucsf.edu
authors.forename: Jason G
authors.initials: JG
authors.lastname: Cyster