Ccl15

Chemokines, a subgroup of cytokines, are small (size between 8 and 10 kDa), chemotactically active proteins (signal proteins). They are common in all vertebrates, some virus types and bacteria. In humans, about 50 chemokines are currently known. A strongly conserved structural feature of all chemokines is a fixed group of cysteine residues that is stabilized by 1 or 2 disulfide bridges. This key structural position in the molecule is responsible for its fixed 3-dimensional structure.

In the CC chemokines, the cysteines follow each other directly (see figure), in the CXC chemokines they are separated (CC = acronym for cysteine-cysteine) by 1, in the CXXXC chemokines by 3 other amino acids. Chemokines are produced and secreted by a large number of immune cells. They transmit their signals by binding to chemokine receptors via G-proteins. Some chemokines have a pro-inflammatory effect, others have a regulatory effect on the development and homeostasis of tissues.

CCL15, also known as leukotactin or CC-chemokine ligand 15, is kleines a cytokine of the CC chemokine family encoded by the CCL15 gene, which is located on chromosome 17 in humans in the vicinity of the CCL14 gene. CCL15 is produced by small intestine and colon cells, by cells of hepatocellular (C22.0) and follicular thyroid carcinoma (C73). Furthermore, the so-called "airway smooth muscle cells", the smooth muscle cells of the airways and basophilic granulocytes are important sources of CCL15.

CCL15 acts chemotactically on neutrophil and eosinophil granulocytes, on monocytes/macrophages and T-lymphocytes via the CCR1 and CCR3 receptors. The chemokine plays a pathogenetic role in bronchial asthma. Omalizumab inhibits the production of CCL15.

CCL15 is also expressed by hepatocytes and hepatocellular carcinoma cells. Serum levels of this chemokine could be an important diagnostic and prognostic marker for this tumor.

CCL15 is expressed in high concentrations in follicular thyroid carcinoma (C73), and in low concentrations in follicular thyroid adenoma. It is believed that CCL15 is responsible for the infiltration of the tumor parenchyma by TAMs (tumor-associated macrophages).

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