Cytokine

Cytokines are a diverse group of small soluble proteins secreted by cells—primarily immune cells—that act as critical mediators in the regulation of immunity, inflammation, and hematopoiesis. They function as intercellular messengers that orchestrate the proliferation, differentiation, activation, and functional modulation of immune cells during both innate and adaptive responses. Cytokines bind to specific receptors on target cells to initiate signal transduction pathways that regulate gene expression relevant to cell survival or death. Their actions are essential for mounting effective defenses against pathogens but must be tightly regulated; dysregulation can result in pathological inflammation or immunodeficiency. Therapeutic strategies often aim at modulating specific cytokines or their receptors to treat diseases characterized by abnormal immune responses—including autoimmune disorders, chronic inflammatory conditions, infections like COVID‑19 with severe CRS manifestations—and some cancers through engineered variants or receptor antagonists/agonists.

Other names

Immunomodulatory cytokineImmune system cytokineCytokine regulatorImmune signaling protein