Figure 1. Toll-like receptor signaling.

TLRs bind bacterial and viral pathogen-associated molecular patterns (PAMPs), leading to the activation of proinflammatory and anti-viral signaling pathways including NF-κB and IRF3/IRF7, respectively. Activation of these pathways is mediated by two key adaptor molecules MyD88 and Trif. Key biological effects of NF-κB activation include prevention of apoptosis and increased inflammation. Type I interferon induces anti-viral and anti-tumor immunity.