TNF and infection: Upon the recognition of viral pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), such as retinoic acid-inducible gene I-like receptors (RLRs), toll-like receptors (TLRs), C-type lectin receptors (CLRs) or NOD-like receptors (NLRs) (1, 2), various inflammatory cytokines including interleukin (IL) 6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNFα) are produced in the host in response to the infection (3–5).