C-X-C motif chemokine 11 (CXCL11) is a 73 amino acid Cys-X-Cys chemokine that induces calcium release in interleukin-activated T-cells and may play a role in skin immune responses and CNS diseases which involve T-cell recruitment. It is also known as interferon gamma-inducible protein 9 (IP-9) and interferon-inducible T-cell alpha chemoattractant (I-TAC). CXCL11 is a ligand for the G protein coupled receptors CXCR3 and CXCR7 and is chemotactic for interleukin-stimulated T-cells but not unstimulated T-cells, neutrophils or monocytes. CXCL11 is expressed at high levels in peripheral blood leukocytes, pancreas and liver astrocytes, moderate levels in the thymus, spleen and lung, and at low levels in the placenta, prostate and small intestine. In skin disorders CXCL11 may also be found in epidermal basal layer keratinocytes. CXCL11 is induced by IFNG/IFN-gamma and IFNB1/IFN-beta. Induction by IFNG/IFN-gamma is enhanced by TNF in monocytes, dermal fibroblasts and endothelial cells, and by IL-1 in astrocytes. Cytokines are a family of secreted proteins involved in immunoregulatory and inflammatory processes. The CXC cytokines are chemotactic cytokines characterized by two cysteines separated by one amino acid that induce directed chemotaxis in nearby responsive cells. Recombinant human CXCL11 from Molecular Innovations is provided as a native untagged protein. This chemokine is expressed in E. coli then processed, refolded and purified to yield the native, secreted form of the mature chemokine. >98percent pure by SDS-PAGE, HPLC, MALDI-MS and NMR analysis. CXCR3 activity verified by intracellular calcium flux using commercially available CXCR3 expressing cells. Add deionized water to desired volume, aliquot and freeze unused portion.