June 2021
Vol 6, Issue 60

About The Cover

Cover image expansion

ONLINE COVER Chemical Confinement of Germinal Center B Cells. This month's cover is an immunofluorescence image showing the spleen of a preimmunized mouse injected one day earlier with B cells (in green) expressing the human P2RY8 receptor. Gallman et al. observed that retention of the transferred B cells in germinal centers, defined by a network of follicular dendritic cells (in red), was maintained by a repulsive gradient of S-geranylgeranyl-ʟ-glutathione (GGG), a P2RY8 ligand exported from B cells in the outer follicle via the Abcc1 transporter protein. A Focus commentary by Stoler-Barak and Shulman explores how GGG gradients are established and maintained to enable germinal centers to support the affinity maturation of B cell–encoded immunoglobulins. [CREDIT: GALLMAN ET AL./SCIENCE IMMUNOLOGY]