Chemokines

The 47 human chemokines regulate cell adhesion and migration of leukocytes. Cells are stimulated to move up the concentration gradient of the chemokine (toward the cell releasing it). They are between 8 and 10 kDa with two disulfides.

Types of chemokines

CC chemokines

Also known as $\beta$-chemokines

• Act on monocytes, lymphocytes, and leukocytes
• CCL1-CCL28
• Produced by leukocytes, endothelial cells, epithelial cells, resident macrophages, fibroblasts, activated T cells (sometimes), and stromal cells
• CXC (AKA $\alpha$-chemokines)
• Some but not all have the “ELR” motif preceding the first cysteine; these support migration of neutrophils. The others on monocytes, lymphocytes, and leukocytes
• CXCL1 to CXCL17
• Produced by leukocytes, endothelial cells, epithelial cells, resident macrophages, fibroblasts, and stromal cells

CX3C

• Specificity of binding to glycosaminoglycans on surface of endothelial cells depends on number of repeats; these then display them to chemokine receptors or migrating cells.
• Production stimulated by TNF, IL-17, IL-1.