Human lupus autoantibody–DNA complexes activate DCs through cooperation of CD32 and TLR9
Terry K. Means, … , Douglas T. Golenbock, Andrew D. Luster
Terry K. Means, … , Douglas T. Golenbock, Andrew D. Luster
Published February 1, 2005
Citation Information: J Clin Invest. 2005;115(2):407-417. https://doi.org/10.1172/JCI23025.
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Human lupus autoantibody–DNA complexes activate DCs through cooperation of CD32 and TLR9

Abstract

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by pathogenic autoantibodies against nucleoproteins and DNA. Here we show that DNA-containing immune complexes (ICs) within lupus serum (SLE-ICs), but not protein-containing ICs from other autoimmune rheumatic diseases, stimulates plasmacytoid DCs (PDCs) to produce cytokines and chemokines via a cooperative interaction between Toll-like receptor 9 (TLR9) and FcγRIIa (CD32). SLE-ICs transiently colocalized to a subcellular compartment containing CD32 and TLR9, and CD32+, but not CD32–, PDCs internalized and responded to SLE-ICs. Our findings demonstrate a novel functional interaction between Fc receptors and TLRs, defining a pathway in which CD32 delivers SLE-ICs to intracellular lysosomes containing TLR9, inducing a signaling cascade leading to PDC activation. These data demonstrate that endogenous DNA-containing autoantibody complexes found in the serum of patients with SLE activate the innate immune system and suggest a novel mechanism whereby these ICs contribute to the pathogenesis of this autoimmune disease.

Authors

Terry K. Means, Eicke Latz, Fumitaka Hayashi, Mandakolathur R. Murali, Douglas T. Golenbock, Andrew D. Luster

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Figure 1

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Purified anti-DNA–containing ICs in SLE serum induce cellular activation...
Purified anti-DNA–containing ICs in SLE serum induce cellular activation. (A) Normal human PBMCs were isolated and stimulated with 20% serum isolated from normal patients (ANA–DNA–), non-SLE patients (ANA+DNA–, 4 Sjogren syndrome and 4 rheumatoid arthritis patients), or 5 SLE patients (ANA+DNA+). After 8 hours of stimulation, the cells were harvested for RNA. (B) PBMCs were stimulated for 8 hours with 100 ng/ml of ICs purified from the serum samples in A. Some PBMCs were stimulated with a 20% serum equivalent of protein G precleared SLE serum. (C) Purified subsets of white blood cells were stimulated with 100 ng/ml SLE-ICs for 8 hours. Expression of IL-8 was determined by QPCR and depicted as the number of copies of mRNA per copies of the control mRNA GAPDH. Error bars indicate standard deviation of triplicate measurements. Data are representative of 4 similar experiments.