FIGURE 1.

Antiviral response induced by macrophages. (A) Viruses can infect target cells by interacting with their receptors (green) or by phagocytosis. Macrophages can recognize viral proteins and genomes to trigger an antiviral immune response. When RIG-I-like receptors (RLRs) and Toll-like receptors (TLRs) recognize viral genomes, they activate the NF-κB and interferon regulatory factor signaling pathways, leading to the production of proinflammatory cytokines (i.e., IL-6, IL-1β, and TNF-α) and interferons (IFN). (B) Viruses have mechanisms to hijack the antiviral immune response. For example, some viral proteins can inhibit TLRs and RLRs, inhibiting the activation of those signaling pathways and enhancing viral pathogenesis, as illustrated by an increase in viral genome replication, viral protein expression, and the release of new viral particles.