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Chemokines are a family of chemoattractant cytokines released by tissues in the earliest phases of infection. They are usually produced by a wide variety of cell types in response to bacterial products, viruses, and agents that trigger physical damage. These small proteins directly induce chemotaxis in nearby responsive cells, leading to the movement of the cells toward the source of the chemokines.
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Chemokines Signaling Pathway Chemokines are a family of chemoattractant cytokines released by tissues in the earliest phases of infection. They are usually produced by a wide variety of cell types in response to bacterial products, viruses, and agents that trigger physical damage. These small proteins directly induce chemotaxis in nearby responsive cells, leading to the movement of the cells toward the source of the chemokines. In addition to being known for mediating chemotaxis, chemokines have the exclusive structural characteristics. All identified chemokines are approximately 8-10 kilodaltons in mass and have four cysteine residues in conserved locations that are critical for forming their 3-dimensional shape. Chemokines are divided into 4 groups. The two major families, the CC chemokines and the CXC chemokine, differ in their genetic locations and structural features. CC chemokines, whose genes are mainly found in clusters on chromosome 4 of human, have two adjacent cysteine residues near the amino terminus. CXC chemokines, in which the equivalent cysteine residues are separated by a single amino acid, are mostly clustered in one region of chromosome 17 in human genes. There are also two minor families that have been identified and described. C chemokines are the one type which has lost the first or third cysteines. The other one is CX3C family that contains three amino acids between first two cysteines.
