Figure 1.

Innate immune responses of a mammalian phagocyte infected with Legionella pneumophila. A schematic representation of the pathways activated in a phagocyte after infection with L. pneumophila. The red boxes indicate L. pneumophila-associated molecular patterns important for the activation of pattern recognition receptors. Blue boxes indicate molecules or processes involved in the cell-autonomous restriction of L. pneumophila replication. LCV, Legionella-containing vacuole; Lpn, L. pneumophila; Dot/Icm, type IVB secretion system; IL, interleukin; IL-18R, IL-18 receptor; TLR, toll-like receptor; MyD88, myeloid differentiation primary response gene 88; NF-κB, nuclear factor kappa B; NOD, nucleotide-binding oligomerization domain-containing protein; RIP2, receptor interacting protein 2; Pol III, RNA polymerase III; RIG-I, retinoic-acid-inducible protein I; IPS-I, IFN-β promoter stimulator 1 (also known as MAVS, mitochondrial antiviral signaling); IRF3, interferon regulatory factor 3; NAIP5, neuronal apoptosis inhibitory protein 5; NLRC4, NLR family CARD domain-containing protein 4.