TLR3 and infection: For example, compared with infection with low pathogenicity influenza virus (IAV) strains, lethal IAV strain infection preferentially upregulated TLR3 to a greater extent, which induced dysregulation of cytokines such as IL-6 and TNF-α and enhanced viral replication (Kalaiyarasu et al., 2016; Huo et al., 2018).