Helicobacter pylori Infection Elicits Type I Interferon Response in Human Monocytes via Toll-Like Receptor 8 Signaling.

colonization and persistence could precede gastric adenocarcinoma. Elucidating immune recognition strategies of is therefore imperative to curb chronic persistence in the human host. Toll-like receptor 7 (TLR7) and TLR8 are widely known as viral single-stranded RNA (ssRNA) sensors yet less studied in the bacteria context. Here, we investigated the involvement of these receptors in the immunity to . Human THP-1 monocytic cells were infected with , and the expression levels of human Toll-like receptors (TLRs) were examined. The roles of TLR7 and TLR8 in response to infection were further investigated using receptor antagonists. Among all TLR transcripts examined, TLR8 exhibited the most prominent upregulation, followed by TLR7 in the THP-1 cells infected with J99 or SS1 strains. infection-mediated IFN- and IFN- transactivation was significantly abrogated by the TLR7/8 (but not TLR7) antagonist. Additionally, TLR7/8 antagonist treatment reduced infection-mediated phosphorylation of interferon regulatory factor 7 (IRF7). Our study suggests a novel role of TLR8 signaling in host immunity against through sensing live bacteria to elicit the production of type I interferon.