In:
The Journal of Immunology, The American Association of Immunologists, Vol. 198, No. 1_Supplement ( 2017-05-01), p. 77.12-77.12
Abstract:
Bacterial biofilms are associated with numerous human infections. The predominant protein expressed in enteric biofilms is amyloid curli which forms immunogenic complexes with DNA. Infection with curli-expressing bacteria or systemic exposure to purified curli-DNA complexes triggers autoimmunity via the generation type I interferons (IFNs) and anti-double stranded (ds) DNA autoantibodies. DNA complexed with curli stimulates Toll-like receptor (TLR) 9 through a two-step mechanism. First, the cross beta-sheet structure of curli is bound by cell-surface TLR2, enabling internalization of the complex into endosomes. After internalization, the curli-DNA immune complex binds strongly to TLR9, inducing production of type I IFNs. Upon stimulation of macrophages with curli-DNA complexes, only 5% of TLR2−/− macrophages harbored intracellular curli, suggesting that TLR2 drives the internalization of curli-DNA complexes. Suppression of TLR2 internalization led to a significant decrease in Ifnβ expression. Structural analysis using small-angle X-ray scattering revealed that incorporation of DNA into curli fibrils results in the formation of ordered curli-DNA immune complexes resulting in optimal spacing to TLR9. Production of anti-dsDNA autoantibodies and type I IFNS in response to curli-DNA fibers was attenuated in the TLR2−/−, TLR9 mutant, and TLR2−/− - TLR9 mutant mice compared to wildtype mice, suggesting that TLR2 and TLR9 are critical for the autoimmune immune response. Overall, our results identify a pivotal series of events that leads to the severe pro-autoimmune effects of amyloid-expressing bacteria.
Type of Medium:
Online Resource
ISSN:
0022-1767
,
1550-6606
DOI:
10.4049/jimmunol.198.Supp.77.12
Language:
English
Publisher:
The American Association of Immunologists
Publication Date:
2017
detail.hit.zdb_id:
1475085-5
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