Innate Immune Response Mechanisms in Inflammatory Conditions

The innate immune system constitutes the body’s first line of defence against invading pathogens and cellular stress. Central to this response are pattern recognition receptors (PRRs), including Toll-like receptors, NOD-like receptors and RIG-I-like receptors, which detect pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). Upon ligand binding, PRRs initiate signalling cascades that activate transcription factors such as NF-κB and IRFs, driving the release of pro-inflammatory cytokines and type I interferons. Inflammasomes assemble in the cytosol to process interleukin-1β and interleukin-18, amplifying the inflammatory milieu. Neutrophils and macrophages are rapidly recruited to sites of injury or infection, where they phagocytose microbes, release reactive oxygen species and form neutrophil extracellular traps. Endothelial cells respond to circulating PAMPs and DAMPs by up-regulating adhesion molecules and altering barrier function, which can exacerbate tissue damage in sterile or infectious contexts. Crosstalk between innate and adaptive immunity is mediated through antigen presentation and cytokine networks, shaping longer-term immune memory. Dysregulation of innate pathways underlies a broad spectrum of inflammatory diseases, from sepsis and acute lung injury to chronic autoimmune disorders and ischaemia–reperfusion injury. Understanding these mechanisms informs the development of targeted therapies that modulate PRR signalling, inhibit inflammasome assembly or limit deleterious neutrophil activity.

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Innate Immune Response Mechanisms in Inflammatory Conditions publication trend

The graph below shows the total number of articles in innate immune response mechanisms in inflammatory conditions across all publications each year (not limited to Nature Index journals).

Technical terms

Pattern recognition receptors (PRRs): Germline-encoded receptors that detect conserved microbial or host-derived danger motifs to trigger innate signalling.

Damage-associated molecular patterns (DAMPs): Endogenous molecules released by stressed or dying cells that initiate sterile inflammation.

Pathogen-associated molecular patterns (PAMPs): Conserved molecular structures of microbes recognised by PRRs.

Inflammasome: Cytosolic multiprotein complex that activates caspase-1, enabling maturation and secretion of IL-1β and IL-18.

Neutrophil extracellular traps (NETs): Networks of chromatin and granule proteins expelled by neutrophils to ensnare and kill pathogens.

References

1. Enterotoxigenic Escherichia coli heat labile enterotoxin affects neutrophil effector functions via cAMP/PKA/ERK signaling. Gut Microbes (2024).
2. Bacterial extracellular vesicles repress the vascular protective factor RNase1 in human lung endothelial cells. Cell Communication and Signaling (2023).
3. Danger- and pathogen-associated molecular patterns recognition by pattern-recognition receptors and ion channels of the transient receptor potential family triggers the inflammasome activation in immune cells and sensory neurons. Journal of Neuroinflammation (2015).