Induction of CCL2 (MCP-1) by IL-33 in human umbelical cord blood mast cells

Mast cells, which derive from a bone marrow progenitor and mature in tissues, are important for allergic reactions, but also in inflammation, autoimmunity, and T-cell-mediated immune responses. The addition of certain cytokines to human umbilical cord blood-derived cultured mast cells have been shown to augment IgE-induced production of distinct cytokines, without histamine secretion. CCL2/MCP-1 is a beta chemokine capable of attracting and activating lymphocytes, macrophages, memory T cells and basophilic cells, but not neutrophils. CCL2/MCP-1 regulates the recruitment of inflammatory cells into tissue during inflammation and allergy. IL-33 belongs to the IL-1 family and binds to the ST2 receptor which has high homology to IL-1 receptor and has biological activities. IL-33, causes allergic inflammation and exerts significant biological effects both in vivo and in vitro. IL-33 induces expression of several cytokines and chemokines, resulting in severe inflammatory and allergic diseases. However, our know:ledge regarding the effects of these cytokines on human mast cell functions is limited. Here, using human umbilical cord blood mast cells (HUCBMCs) as a valid model, we found that IL-33 induces CCL2/MCP-1 release in HUCBMCs. The release was higher at 24 h incubation compared with 12 h. This study documents the ability of IL-33 to directly stimulate Human umbilical cord blood mast cells (UCBMCs) to produce CCL2/MCP-1. We show that IL-33 is a strong activator of human mast cells capable of inducing CCL2/MCP-1 released at translational level. The present data describe an additional biological activity of IL-33, suggesting that this cytokine may have an important effect on the recruitment of inflammatory cells in allergic diseases.