Specificity
Small inducible cytokine A23 precursor (CCL23), or CK-b-8, is a chemokine that binds to the receptor CCR1. It is involved in the immune response and inhibits production of polymorphonuclear leukocytes (PMNs) and monocytes in bone marrow. In addition, CCL23 has a splice variant, CK-b-8-1, and both variants chemoattract lymphocytes, monoctyes and neutrophils. CCL23 also promotes angiogenesis and endothelial cell migration via its actions on the CCR1 receptor. Proinflammatory proteases cleave an N-terminal domain of CCL23, improving the potency of its CCR1-mediated signaling up to 1000- fold in vitro. N-truncated CCL23 is found in high levels in synovial fluids of rheumatoid arthritis patients, suggesting a role of protease release during an inflammatory response. High levels of CCL23 mRNA expression occur in human fetal bone osteoblasts and chondrocytes, indicating a possible role for CCL23 in the recruitment of osteoclast precursors to the sites of bone reabsorption.
