Published in

Public Library of Science, PLoS ONE, 3(10), p. e0119727, 2015

DOI: 10.1371/journal.pone.0119727

Links

Tools

Export citation

Search in Google Scholar

Innate Immune Response to Streptococcus pyogenes Depends on the Combined Activation of TLR13 and TLR2

This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

Full text: Download

Green circle
Preprint: archiving allowed
Green circle
Postprint: archiving allowed
Green circle
Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

Innate immune recognition of the major human-specific Gram-positive pathogen Strepto-coccus pyogenes is not understood. Here we show that mice employ Toll-like receptor (TLR) 2-and TLR13-mediated recognition of S. pyogenes. These TLR pathways are non-redundant in the in vivo context of animal infection, but are largely redundant in vitro, as only inactivation of both of them abolishes inflammatory cytokine production by macrophages and dendritic cells infected with S. pyogenes. Mechanistically, S. pyogenes is initially recognized in a phagocytosis-independent manner by TLR2 and subsequently by TLR13 upon in-ternalization. We show that the TLR13 response is specifically triggered by S. pyogenes rRNA and that Tlr13 −/− cells respond to S. pyogenes infection solely by engagement of TLR2. TLR13 is absent from humans and, remarkably, we find no equivalent route for S. pyogenes RNA recognition in human macrophages. Phylogenetic analysis reveals that TLR13 occurs in all kingdoms but only in few mammals, including mice and rats, which are naturally resistant against S. pyogenes. Our study establishes that the dissimilar expression of TLR13 in mice and humans has functional consequences for recognition of S. pyogenes in these organisms.