This illustration shows the four main functions of B cells in immune-mediated diseases of the CNS.
(A) CD19-CD20 low CD27++CD138+long-lived plasma cells and CD19 low CD27+CD138+ plasma blasts secrete antibodies that contribute to tissue damage via antibody-dependent cell-mediated cytotoxicity or complement activation.
(B) CD19+CD20+ activated B cells are potent APC that mediate cytokine secretion and clonal expansion of cytotoxic T cells.
(C) Production of pro- or anti-inflammatory cytokines by CD19+CD20+ B cells may affect the activation of macrophages or T cells.
(D) Plasma cells, plasma blasts and CD20+ B cells may be involved in de novo formation and maintenance of ectopic germinal centers in the intermeningeal spaces (neolymphogenesis).
Abbreviations: APC: Antigen-Presenting Cells; BCR: B Cell Receptor; DC: Dendritic Cell; MHC: Major Histocompatibility Complex; TCR: T Cell Receptor. Illustration modified from Barun and Bar-or [95].
