T Cell Epitope Mimicry Between Sjögren's Syndrome Antigen A (SSA)/Ro60 and Oral, Gut, Skin and Vaginal Bacteria

Szymula et al., Clin. Immunol. (2014) - PMID: 24576620

Product(s) used in this publication:  PepTrack™ Peptide Libraries


This study was undertaken to test the hypothesis that Sjogren's syndrome Antigen A (SSA)/Ro60-reactive T cells are activated by peptides originating from oral and gut bacteria. T cell hybridomas generated from HLA-DR3 transgenic mice recognized 3 regions on Ro60, with core epitopes mapped to amino acids 228-238, 246-256 and 371-381. BLAST analysis identified several mimicry peptides, originating from human oral, intestinal, skin and vaginal bacteria, as well as environmental bacteria. Amongst these, a peptide from the von Willebrand factor type A domain protein (vWFA) from the oral microbe Capnocytophaga ochracea was the most potent activator. Further, Ro60-reactive T cells were activated by recombinant vWFA protein and whole Escherichia coli expressing this protein. These results demonstrate that peptides derived from normal human microbiota can activate Ro60-reactive T cells. Thus, immune responses to commensal microbiota and opportunistic pathogens should be explored as potential triggers for initiating autoimmunity in SLE and Sjögren's syndrome.

Copyright © 2014 Elsevier Inc. All rights reserved.


Microbiota; Molecular mimicry; Ro60/SSA; SLE; Sjögren's syndrome; T epitopes

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