Anti-CCL23 monoclonal antibody, clone FQS22474

Background: CCL23 (MPIF1/CK-BETA-8) is a novel CC chemokine that plays important roles in the inhibition of myeloid progenitor cell development, the selective recruitment of resting T lymphocytes and monocytes, and the potentiation of VEGF-induced proliferation and migration of human endothelial cells. Since eosinophils participate in the pathogenesis of airway remodeling, we examined CCL23 production and release by human eosinophils in vitro. Methods: Using Ficoll and antibody-coated immunomagnetic beads, eosinophils and other blood cells were purified from peripheral blood samples obtained from normal subjects and mildly allergic patients. Eosinophils were cultured in the presence of 10 ng/ml granulocyte-macrophage colony-stimulating factor (GM-CSF), 10 ng/ml IL-5, 100 ng/ml IFN-gamma, 100 ng/ ml IFN-alpha, or immobilized secretory IgA (sIgA). Total mRNA was extracted after 6 h of culture, and mRNA expression was measured using a microarray and RT-PCR. The CCL23 concentrations in the supernatants and cell lysates after 24 and 48 h of culture were measured by ELISA. Results: CCL23 mRNAs (both CK-beta 8-1 and CK-beta 8) were constitutively expressed in fresh eosinophils, and their expression levels were higher than in other types of blood cells. CCL23 mRNAs were significantly increased by stimulation with GM-CSF and IL-5 and slightly by IFN-alpha and immobilized sIgA. Fresh eosinophils contained trace amounts of CCL23 protein. CCL23 was significantly released into the supernatant when the eosinophils were stimulated with GM-CSF or IL-5 but not with IFN-gamma or immobilized sIgA. Conclusion: Our data suggest that eosinophils produce and release CCL23 and may be involved in some in vivo physiological and pathological conditions. Copyright (C) 2011 S. Karger AG, Basel

We have previously demonstrated that a tartrate-resistant acid phosphatase (TRAP)-positive subpopulation of mononuclear cells isolated from collagenase digests of human osteoclastoma tissue exhibits an osteoclast phenotype and can be induced to resorb bone. Using these osteoclast precursors as a model system, we have assessed the chemotactic potential of 16 chemokines. Three CC chemokines, the recently described CK beta-8, RANTES, and MIP-1 alpha elicited significant chemotactic responses. In contrast, 10 other CC chemokines (MIP-1 beta, MCP-1, MCP-2, MCP-3, MCP-3, HCC-1, eotaxin-2 PARC, SLC, ELC) and 3 CXC chemokines (IL-8, CROalpha, SDF-1) were inactive. None of these chemokines showed any chemotactic activity for either primary osteoblasts derived from human bone explants or the osteoblastic MG-63 cell line. The identity of the osteoclast receptor that mediates the chemotactic response remains to be established. However, all three active chemokines have been reported to bind to CCR1 and cross-desensitization studies demonstrate that RANTES and MIP-la can partially inhibit the chemotactic response elicited by CK beta-8. CK beta-8, the most potent of the active CC chemokines (ECmax 0.1-0.3 nM), was further characterized with regard to expression in human bone and cartilage. Although expression is not restricted to these tissues, CK beta-8 mRNA was shown to be highly expressed in osteoblasts and chondrocytes in human fetal bone by in situ hybridization. In addition, CK beta-8 protein was shown to be present in human osteophytic tissue by immunolocalization. These observations suggest that CK beta-8, and perhaps other chemokines, may play a role in the recruitment of osteoclast precursors to sites of bone resorption. (C) 2000 Wiley-Liss, Inc.