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J Biol Chem. 2012 Feb 17;287(8):5310-6. doi: 10.1074/jbc.M111.316356. Epub 2012 Jan 3.

Inhibition of antigen trafficking through scavenger receptor A.

Author information

1
Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA.

Abstract

B cell acquisition and presentation of specific autoantigens (auto-Ags) are thought to play an important and complex role in autoimmunity development. We previously identified scavenger receptor A (SR-A) as an early target in altering B cell-mediated autoimmunity. SR-A is highly expressed on professional antigen-presenting cells such as macrophages (MΦs) and dendritic cells (DCs). In this study, we demonstrate that SR-A is responsible for controlling B cell interactions with DCs/MΦs to promote Ag transfer from B cells to DCs/MΦs. We established a high-throughput ELISA-based screen to identify novel SR-A inhibitors, the specificity of which was determined by dose dependence and Biacore surface plasmon resonance testing. We identified small molecule inhibitors (SMIs) able to reduce SR-A-mediated Ag transfer in human cells. In particular, the SMIs prevented SR-A-positive cells from accumulating/loading Ag over time. Furthermore, we determined that one SMI, sennoside B, can reduce SR-A-mediated capture of B cells. Finally, SMI-mediated decreases in Ag transfer or accumulation reduced T cell proliferation in vitro and in vivo. These observations demonstrate that B cell-DC/MΦ interactions are conducive to promoting Ag trafficking between these cell types via SR-A. Inhibitors of SR-A may provide a novel therapeutic strategy in ameliorating autoimmune disease development.

PMID:
22215667
PMCID:
PMC3285311
DOI:
10.1074/jbc.M111.316356
[Indexed for MEDLINE]
Free PMC Article

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