TLR7 and viral infectious disease: In detail, TLR7 favors the production of cytokines involved in CD4+ T helper 17 (Th17) cell polarization (IL-1β, IL-6, and IL-23) after virus infection with MV and VSV, whereas TLR8 promotes the TH1-promoting cytokine response and type I IFN production after viral infection with ECMV.