The surface molecule PD-1 is a key to producing long-lived antibody-secreting cells. Previous work has shown that PD-1 acts as an inhibitor to constrain immune responses during chronic infection. The findings described in a report published this week in Nature Immunology, show a new positive role for PD-1.
Mark Shlomchik and colleagues show PD-1 to be necessary for the generation of long-lived antibody producing cells. PD-1 expressed on the immune system's helper T cells communicates with its receptors ― PD-L1 and PD-L2 ― expressed on B cells of the immune system. This interaction occurs in specialized areas of lymph nodes and spleen called germinal centers, where B cells are 'educated' to become specific antibody producers. Mice lacking PD-1 or its receptors have defective germinal centers and fail to generate large numbers of memory antibody-secreting B cells.