Memory B cells also rest in the bone marrow and wait for reactivation

Publication from the DRFZ in Nature Communications. Surprisingly for the scientific community, Mir-Farzin Mashreghi, Andreas Radbruch and colleagues* have now been able to show that isotype switched memory B cells attach to specific mesenchymal stromal cells of the bone marrow and survive. Isotype switched memory B-cells ensure a rapid immune response upon reinfection with a pathogen. They are precursors of memory plasma cells, which release a high number of protective antibodies against pathogens. Thus isotype switched memory B cells protect us from infections by rapidly differentiating to antibody producing plasma cells. Until now, it was only known that memory plasma cells are located in the bone marrow. It was not clear where memory B cells are located and kept alive in the absence of their specific pathogen. A new genetic analysis on single cell level (Single Cell transcriptome study) has now shown for the first time that a population is located exclusively in the spleen, while a population of quiescent memory B cells is found only in the bone marrow. Three further resident populations are present in spleen and bone marrow. These results are of crucial importance for the development of vaccination strategies.