A paper in Nature:Nature 509, 637–640 (29 May 2014) doi:10.1038/nature13300 describes in detail the complex ways B cells travel betwenn in dark und the light zone during clonal expansion and hypermutation. That is remarkable since the autors use different techniques for the labelling of cells. Aside from methodological point of view this shows complex interactions with T cells as one driving force in this process.