[PDF][PDF] Follicular dendritic cell activation by TLR ligands promotes autoreactive B cell responses

A Das, BA Heesters, A Bialas, J O'Flynn, IR Rifkin… - Immunity, 2017 - cell.com
A Das, BA Heesters, A Bialas, J O'Flynn, IR Rifkin, J Ochando, N Mittereder, G Carlesso
Immunity, 2017cell.com
A hallmark of autoimmunity in murine models of lupus is the formation of germinal centers
(GCs) in lymphoid tissues where self-reactive B cells expand and differentiate. In the host
response to foreign antigens, follicular dendritic cells (FDCs) maintain GCs through the
uptake and cycling of complement-opsonized immune complexes. Here, we examined
whether FDCs retain self-antigens and the impact of this process in autoantibody secretion
in lupus. We found that FDCs took up and retained self-immune complexes composed of …
Summary
A hallmark of autoimmunity in murine models of lupus is the formation of germinal centers (GCs) in lymphoid tissues where self-reactive B cells expand and differentiate. In the host response to foreign antigens, follicular dendritic cells (FDCs) maintain GCs through the uptake and cycling of complement-opsonized immune complexes. Here, we examined whether FDCs retain self-antigens and the impact of this process in autoantibody secretion in lupus. We found that FDCs took up and retained self-immune complexes composed of ribonucleotide proteins, autoantibody, and complement. This uptake, mediated through CD21, triggered endosomal TLR7 and led to the secretion of interferon (IFN) α via an IRF5-dependent pathway. Blocking of FDC secretion of IFN-α restored B cell tolerance and reduced the amount of GCs and pathogenic autoantibody. Thus, FDCs are a critical source of the IFN-α driving autoimmunity in this lupus model. This pathway is conserved in humans, suggesting that it may be a viable therapeutic target in systemic lupus erythematosus.
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