title: Thymic B Cells and Central T Cell Tolerance.
abstract: Central T cell tolerance is believed to be mainly induced by thymic dendritic cells and medullary thymic epithelial cells. The thymus also harbors substantial numbers of B cells. These may arise though intrathymic B lymphopoiesis or immigration from the bloodstream. Importantly, and in contrast to resting "mainstream" B cells in the periphery, thymic B cells display elevated levels of MHC class II and constitutively express CD80. Arguably, their most unexpected feature is the expression of autoimmune regulator. These unique features of thymic B cells result from a licensing process that involves cross-talk with CD4 single-positive T cells and CD40 signaling. Together, these recent findings suggest that B cells play a more prominent role as thymic APCs than previously appreciated.
authors.affiliation: Institute for Immunology, Ludwig-Maximilians-University Munich , Munich , Germany.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Yamano
authors.affiliation: Institute for Immunology, Ludwig-Maximilians-University Munich , Munich , Germany.
authors.forename: Madlen
authors.initials: M
authors.lastname: Steinert
authors.affiliation: Institute for Immunology, Ludwig-Maximilians-University Munich , Munich , Germany.
authors.forename: Ludger
authors.initials: L
authors.lastname: Klein
keywords: Aire; B cells; CD40; antigen presentation; central tolerance; class-switching; germinal center