Regulatory B cell (Breg) (Breg)

Regulatory B cells (Bregs) are a specialized subset of B lymphocytes that play a pivotal role in maintaining immune homeostasis and promoting peripheral tolerance. Their primary mechanism of action is the production of anti-inflammatory cytokines, most notably Interleukin-10 (IL-10), which suppresses the activity of pro-inflammatory cells such as Th1 and Th17 cells and dendritic cells (Mauri & Bosma, 2012). In humans, Bregs are often identified within the CD24hiCD38hi or CD24hiCD27+ (memory) B cell compartments, the latter of which is frequently associated with IgG4 production and allergen tolerance (van de Veen et al., 2013). While Bregs are beneficial in preventing autoimmune diseases like systemic lupus erythematosus and multiple sclerosis, their presence in the tumor microenvironment can be detrimental by inhibiting anti-tumor immune responses (Tedder, 2011). Although Bregs are a cell population rather than a single molecular receptor, they are increasingly viewed as a therapeutic focus for induction or adoptive cell therapy in inflammatory conditions. However, the use of pan-B cell depleting agents like Rituximab can inadvertently eliminate these regulatory subsets, potentially leading to paradoxical flares in some patients (Rosser & Mauri, 2015).

Other names

B10 cellIL-10-producing B cellSuppressive B cellBr1 cellRegulatory B lymphocyteCD24hiCD38hi B cellCD24hiCD27+ B cell

Regulatory B cells suppress immune responses primarily through the secretion of Interleukin-10 (IL-10), which downregulates the expression of MHC class II and co-stimulatory molecules on antigen-presenting cells and inhibits the production of pro-inflammatory cytokines by T cells (Mauri & Bosma, 2012). They also produce TGF-beta and IL-35 and can induce the differentiation of naive T cells into regulatory T cells (Tregs) through both cytokine secretion and direct cell-cell contact involving molecules like PD-L1 and FasL (Rosser & Mauri, 2015).