biostudies-literatureHam GNational Research Foundation of Korea7220https://www.ebi.ac.uk/biostudies/studies/S-EPMC12923743biostudies-literatureUnknown16(1)Severe fever with thrombocytopenia syndrome virus (SFTSV) is a negative-sense RNA virus that can cause high fever, thrombocytopenia, and multiple-organ dysfunction. Toll-like receptor 7 (TLR7) can recognize single-stranded RNA viruses and induce type I interferons (IFNs). Although type I IFNs play a critical role in SFTSV infection, the role of TLR7 remains incompletely understood. To investigate the role of TLR7 signaling in SFTSV pathogenesis, TLR7-deficient (TLR7^-/-) mice and wild-type (WT) mice were inoculated with SFTSV. TLR7^-/- mice exhibited severe weight loss and elevated viral RNA levels in various organs compared to WT mice. These mice also showed marked white pulp atrophy in the spleen and increased immunoreactivity for SFTSV nucleoprotein antigen. To furthScientific reportsThe role of toll-like receptor 7 signaling in mice infected by severe fever with thrombocytopenia syndrome virus.PMC12923743RS-2019-NR040075Kim BOh SIPark SCTark DChoi JGOh BHam GfalseThe role of toll-like receptor 7 signaling in mice infected by severe fever with thrombocytopenia syndrome virus.Severe fever with thrombocytopenia syndrome virus (SFTSV) is a negative-sense RNA virus that can cause high fever, thrombocytopenia, and multiple-organ dysfunction. Toll-like receptor 7 (TLR7) can recognize single-stranded RNA viruses and induce type I interferons (IFNs). Although type I IFNs play a critical role in SFTSV infection, the role of TLR7 remains incompletely understood. To investigate the role of TLR7 signaling in SFTSV pathogenesis, TLR7-deficient (TLR7^-/-) mice and wild-type (WT) mice were inoculated with SFTSV. TLR7^-/- mice exhibited severe weight loss and elevated viral RNA levels in various organs compared to WT mice. These mice also showed marked white pulp atrophy in the spleen and increased immunoreactivity for SFTSV nucleoprotein antigen. To furth2026-01-01T00:00:00Z2026 Feb2026-07-16T14:46:55.07Z2026-07-09T11:01:59.585ZS-EPMC129237434163925010.1038/s41598-026-37472-4