The expanding family of regulatory B cells

Abstract

Over the last decade it has become evident that in addition to producing antibody, B cells activate the immune system by producing cytokines and via antigen presentation. In addition, B cells also exhibit immunosuppressive functions via diverse regulatory mechanisms. This subset of B cells, known as regulatory B cells (Bregs), contributes to the maintenance of tolerance, primarily via the production of IL-10. Studies in experimental animal models, as well as in patients with autoimmune diseases, have identified multiple Breg subsets exhibiting diverse mechanisms of immune suppression. In this review, we describe the different Breg subsets identified in mice and humans, and their diverse mechanisms of suppression in different disease settings.

Keywords: B cell; Bregs; IL-10; human; immune-suppression; mouse; regulation; regulatory B cells; subsets.

Fig. 1.

Models of Breg development. Several models could explain the existence of numerous Breg subsets. (A) Multi-lineage Bregs. In this model, different Breg subsets arise from individual progenitors. (B) Single lineage Bregs. All the different Bregs subsets described (with the exception of B1) arise from a single progenitor and express a single transcription factor. Bregs are not a terminally differentiated state and can exhibit suppressive functions at different stages of differentiation. (C) Induced Bregs. In this model, any B cell can become regulatory on exposure to specific environmental stimuli and exhibit suppressive capacity. Beff, B effector cell; Pb, plasmablast; Plasma, plasma cell.