Innate immune system pathways

The innate immune system pathways represent the primary, non-specific defense mechanism of the host against pathogens and tissue damage (NIH, 2023). This classification is not a single molecular target but a collective term for various receptors, including Toll-like receptors (TLRs) and RIG-I-like receptors, and their downstream signaling components (StatPearls, 2023). These pathways are responsible for the rapid production of cytokines, chemokines, and the activation of phagocytic cells such as macrophages and neutrophils (PubMed, PMID: 30272035). In drug development, this label is frequently applied to immunomodulators whose precise molecular binding site is either unknown or involves multiple components of the immune system (Nature Reviews Drug Discovery, 2020). For example, Bacillus Calmette-Guérin (BCG) and certain bacterial lysates are used to stimulate these pathways to treat bladder cancer or respiratory infections (FDA, 2022). Therapeutic strategies targeting these pathways aim to either boost the immune response in oncology and infectious disease or dampen it in the context of chronic inflammation (Journal of Clinical Investigation, 2019). Because it lacks a specific molecular identity, this 'target' presents challenges for precise drug design and pharmacokinetic modeling. Monitoring efficacy often involves measuring systemic inflammatory markers rather than target occupancy.

Other names

Innate immunityInnate immune responseNon-specific immune systemBroad innate immune pathways

Modulation of pattern recognition receptors (PRRs) and innate immune cell activation to elicit a broad inflammatory or anti-inflammatory response (PubMed, PMID: 31043704).