Ccl28

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

In CC chemokines, the cysteines directly follow each other (see Fig.), in CXC chemokines they are separated (CC = acronym for cysteine-cysteine) by 1, in CXXXC chemokines by 3 other amino acids. Herein we show that CCL15 is processed in human synovial fluid by matrix metalloproteinases (MMPs) and serine proteases. are produced and secreted by a variety of immune cells. They mediate their signals by binding to chemokine receptors via G-proteins. Some chemokines have proinflammatory effects, while others have regulatory effects in tissue formation, homeostasis, and proliferation.

CCL28, also known as C-C motif chemokine ligand 28, is a small human cytokine that belongs to the CC chemokine family. CCL28 is also known as "mucosae-associated epithelial chemokine" or MEC. Like other chemokines (CCl5, CCL7, CCL8, CCL11, CCL13, CCL15, CCL24, CCL27, CCL26) it binds to the chemokine receptors CCR3 and CCR10 and regulates chemotaxis of receptor-expressing cells such as T and B cells, eosinophilic granulocytes. CCL28 is expressed in intestinal cells, lung, mammary gland tissue and salivary glands.

CCL28 is involved in the migration of IgA-producing cells of the mammary gland tissue (Pallister KB et al. 2015), the salivary glands and the mucosa of the intestinal tract. Furthermore, CCL28 is involved in the immune defence against bacterial, mycotic and viral infections (concerns both Gram-negative and Gram-positive infections as well as exposures to HI-viruses and influenza viruses).

CCL28 is upregulated in the mucosal epithelium in bronchial asthma. CCL28 is significantly reduced in saliva secretion in patients with Sjögren's syndrome (M35.0) compared to non-infected patients.

1. Berri M et al (2014) CCL28 involvement in mucosal tissues protection as a chemokine and as an antibacterial peptide. Dev Comp Immunol 44:286-290.
2. Danilova E et al (2015) A role for CCL28-CCR3 in T-cell homing to the human upper airway mucosa. MucosalImmunol 8:107-114.
3. Hernandez-Molina G et al. (2015) Absence of salivary CCL28 in primary Sjögren's syndrome. Rheumatol Int 35:1431-1434.
4. Mohan T et al (2016) Co-delivery of GPI-anchored CCL28 and influenza HA in chimeric virus-like particles induces cross-protective immunity against H3N2 viruses. J Control Release 233:208-219.
5. Pallister KB et al (2015) Bovine CCL28 Mediates Chemotaxis via CCR10 and Demonstrates Direct Antimicrobial Activity against Mastitis Causing Bacteria. PLoS One 10:e0138084.
6. Thomas MA et al(2015) Structure-function analysis of CCL28 in the development of post-viral asthma. J Biol Chem 290:4528-4536.