Clostridioides difficile Binary Toxin Is Recognized by the Toll-Like Receptor 2/6 Heterodimer to Induce a Nuclear Factor-κB Response

Clostridioides difficile infection (CDI) represents a significant burden on the health care system, one that is exacerbated by the emergence of binary toxin (CDT)-producing hypervirulent C. difficile strains. Previous work from our laboratory has shown that Toll-like receptor 2 (TLR2) recognizes CDT to induce inflammation. Here we explore the interactions of CDT with TLR2 and the impact on host immunity during CDI. We found that the TLR2/6 heterodimer, not TLR2/1, is responsible for CDT recognition, and that gene pathways including nuclear factor-κB and MAPK downstream of TLR2/6 are upregulated in mice with intact TLR2/6 signaling during CDI.