CCL17/TARC ELISA Kit, Human

The inducible chemokine CCL17, previously termed thymus and activation-regulated chemokine (TARC) belonging to the CC chemokine family, is strongly upregulated throughToll-like receptor stimulation. CCL17 and the closely related chemokine CCL22 (MDC) bind to the receptor CCR4, which is known to be expressed on activated/memory cells with a Th2 preference, regulatory T cells, Langerhans cells (LCs), basophils, and macrophages. CCL17 and its receptor have been reported to play a role in endotoxic shock, systemic lupus erythematosus, Hodgkin’s lymphoma, and pulmonary fibrosis. CCL17 is expressed constitutively in thymus, but only transiently in phytohemagglutinin-stimulated peripheral blood mononuclear cells.It was shown that CCL17 is specifically expressed by CD8α−CD11b+DEC205+ dendritic cells (DCs). Moreover, CCL17 plays an essential role in the emigration of DCs from the skin to the skin-draining lymph nodes (LNs).² In addition, it was shown that CCR4 is also highly expressed on both primary malignant cells and leucocytes (tumour-associated macrophages and Treg cells) in these tumour types. Antagonists of CCR4 or CCL17/22 may exert a dual action in these malignancies, inhibiting the pro-tumour immunosuppressive infiltrate as well as having direct effects on cancer cell survival and invasive capacity. Since CCR4 is expressed on only a subset of tumours, there is the potential to select patients expected to be sensitive to CCR4-directed therapies using CCR4 as a companion predictive biomarker.³