title: Germinal Centers: Gaining Strength from the Dark Side.
abstract: Germinal center B cells exist in two conditions, a dark zone state and a light zone state. Two studies in this issue (Dominguez-Sola et al., 2015; Sander et al., 2015) report that Foxo1 deficiency causes an almost complete loss of dark zone cells and an inability to undergo robust antibody affinity maturation.
authors.affiliation: Howard Hughes Medical Institute, Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA. Electronic address: jason.cyster@ucsf.edu.
authors.forename: Jason G
authors.initials: JG
authors.lastname: Cyster