Innate pattern-recognition receptor (PRR)

Innate pattern-recognition receptors (PRRs) are a diverse class of germline-encoded receptors primarily expressed by cells of the innate immune system, such as macrophages, dendritic cells, and neutrophils (StatPearls, 2023). They are specialized to detect conserved molecular structures known as pathogen-associated molecular patterns (PAMPs) found in microbes, as well as damage-associated molecular patterns (DAMPs) released from injured host cells (Nature Reviews Immunology, 2010). Upon activation, PRRs initiate signaling cascades—often involving NF-kappaB or IRF pathways—that lead to the production of pro-inflammatory cytokines, chemokines, and interferons, thereby orchestrating the initial immune response and shaping subsequent adaptive immunity (NIH, 2022). Major families of PRRs include Toll-like receptors (TLRs), NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), and C-type lectin receptors (CLRs). In therapeutic contexts, PRR agonists like imiquimod are utilized as cancer immunotherapies and vaccine adjuvants to enhance immune surveillance, while PRR antagonists are being investigated for treating chronic inflammatory and autoimmune disorders (PubMed, 2021).

Other names

Pattern recognition receptorsPRRsPrimitive immune receptorsInnate immune receptors

Agonism of PRRs triggers downstream signaling pathways like NF-κB and IRF, leading to the secretion of pro-inflammatory cytokines and type I interferons to boost anti-tumor or anti-pathogen immunity. Conversely, PRR antagonism or inhibition of downstream signaling is used to mitigate excessive inflammation in autoimmune diseases and sepsis (Nature Reviews Drug Discovery, 2019).