Chemokiinien

Chemokiinien, commonly referred to in English as chemokines, are a family of small secreted cytokines that regulate the movement and positioning of cells, particularly leukocytes, by guiding them along chemical gradients. They exert their effects by binding to chemokin receptors, a subset of G protein–coupled receptors expressed on target cells, initiating signaling that directs migration, activation, and survival.

Chemokiinien are categorized by the arrangement of conserved cysteine residues near their N-terminus into four main subfamilies: C, CC, CXC, and CX3C. This classification correlates with receptor usage and function. Most chemokiinien are rapidly induced in response to infection, injury, or inflammation, though a number also regulate normal tissue homeostasis. They are produced by a variety of cell types, including macrophages, dendritic cells, endothelial cells, fibroblasts, and epithelial cells, often in response to inflammatory stimuli.

Biological roles of chemokiinien include recruitment of specific immune cell subsets to sites of infection or damage, modulation of leukocyte activation, and involvement in processes such as angiogenesis, hematopoiesis, and embryonic development. Some chemokiinien are constitutively expressed to maintain tissue surveillance (homeostatic chemokiinien), while others are induced during inflammatory responses (inflammatory chemokiinien). The resulting chemokine gradients guide cell trafficking, tissue organization, and resolution of inflammation.

Clinical relevance is notable because dysregulation of chemokiinien or their receptors is associated with autoimmune diseases, chronic inflammatory conditions, and cancer metastasis. Therapeutic strategies include chemokiin receptor antagonists and inhibitors that aim to block inappropriate leukocyte recruitment, with approved drugs such as CCR5 and CXCR4 antagonists used in specific indications, and ongoing development for others.