IgM+ memory B cells induced in response to Plasmodium berghei adopt a germinal centre B cell phenotype during secondary infection

HM Pietrzak, LJ Ioannidis, DS Hansen - Parasitology, 2020 - cambridge.org
HM Pietrzak, LJ Ioannidis, DS Hansen
Parasitology, 2020cambridge.org
Emerging evidence started to delineate multiple layers of memory B cells, with distinct
effector functions during recall responses. Whereas most studies examining long-lived
memory B cell responses have focussed on the IgG+ memory B cell compartment, IgM+
memory B cells have only recently started to receive attention. It has been proposed that
unlike IgG+ memory B cells, which differentiate into antibody-secreting plasma cells upon
antigen re-encounter, IgM+ memory B cells might have the additional capacity to establish …
Emerging evidence started to delineate multiple layers of memory B cells, with distinct effector functions during recall responses. Whereas most studies examining long-lived memory B cell responses have focussed on the IgG+ memory B cell compartment, IgM+ memory B cells have only recently started to receive attention. It has been proposed that unlike IgG+ memory B cells, which differentiate into antibody-secreting plasma cells upon antigen re-encounter, IgM+ memory B cells might have the additional capacity to establish secondary germinal centre (GC) responses. The precise function of IgM+ memory B cells in the humoral immune response to malaria has not been fully defined. Using a murine model of severe malaria infection and adoptive transfer strategies we found that IgM+ memory B cells induced in responses to P. berghei ANKA readily proliferate upon re-infection and adopt a GC B cell-like phenotype. The results suggest that that IgM+ memory B cells might play an important role in populating secondary GCs after re-infection with Plasmodium, thereby initiating the induction of B cell clones with enhanced affinity for antigen, at faster rates than naive B cells.
Cambridge University Press