Immunsignalering

Immunsignalering is the process by which the immune system detects threats and coordinates responses through intercellular communication. It encompasses detection of pathogens, damaged cells, and abnormal molecules by cells of the innate immune system (for example macrophages, dendritic cells, neutrophils, natural killer cells) and by non-immune cells, followed by intracellular signaling that alters gene expression and cell behavior. Communication occurs through cytokines, chemokines, and other mediators that act in autocrine, paracrine, and, in some cases, endocrine fashion.

Key sensors include pattern recognition receptors such as Toll-like receptors, NOD-like receptors, RIG-I-like receptors, and cytosolic DNA sensors. Activation triggers signaling cascades, notably NF-κB, MAPK, and IRF pathways, leading to production of cytokines (e.g., IL-1, IL-6, TNF-α, interferons) and chemokines. These mediators bind to their receptors on various cells, engaging signaling axes such as JAK-STAT and further modulating immune cell recruitment, differentiation, and effector functions. Dendritic cells link sensing to adaptive immunity by presenting antigens and providing costimulatory signals to T cells.

Regulation is essential to avoid excessive inflammation; mechanisms include anti-inflammatory cytokines (IL-10, TGF-β), regulatory T cells, and negative feedback loops (SOCS proteins). Failure or chronic dysregulation can contribute to autoimmune disease, persistent infections, or cancer progression.

Understanding immune signaling underpins vaccine design, immunotherapies, and anti-inflammatory treatments, while remaining a central topic in immunology research.