1. Viral detection and viral evasion.
Viral detection and viral evasion. (A) Viral detection by the innate immune system. Respiratory viruses are detected extracellularly by TLR2, TLR4, and TLR6; in the endosome by TLR3, TLR7, and TLR9; and in the cytoplasm by RIG-I (retinoic acid-inducible gene I), MDA-5 (melanoma differentiation-associated gene 5), and NLRP3 (NLR family, pyrin domain-containing 3). (B) Viral evasion of the innate immune system. Viruses inhibit the pattern recognition receptors RIG-I and MDA-5 and the downstream molecules IRF3, NF-κB, and JAK/STAT. In some cases the viral protein that inhibits the response has been identified. Abbreviations: AV, adenovirus; CoV, SARS coronavirus; hMPV, human metapneumovirus; IV, influenza virus; PIV, parainfluenza virus, RSV, respiratory syncytial virus; RV, rhinovirus; TLR, Toll-like receptor; IFNAR, interferon alpha receptor; ORF, open reading frame; CASP-1, caspase 1; NS, nonstructural.
John S. Tregoning, and Jürgen Schwarze Clin. Microbiol. Rev. 2010; doi: /CMR