IP-10/CXCL10

CXCL10, also known as interferon γ-induced protein 10 kDa (IP-10), is a cytokine belonging to the CXC chemokine family. CXCL10 exerts its biological effects by binding to CXCR3. CXCL10 is a pleiotropic molecule capable of exerting potent biological functions, including promoting the chemotactic activity of CXCR3+ cells, inducing apoptosis, regulating cell growth and proliferation as well as angiogenesis in infectious and inflammatory diseases and cancer. CXCL10 activates T lymphocytes (Th1), NK cells, macrophages, dendritic and B cells. Alterations in CXCL10 expression levels have been associated with inflammatory diseases including infectious diseases, angiogenesis, immune dysfunction and tumor development^[1]. Human CXCL10 gene, is initially isolated in 1985 by Luster while treating a lymphoma cell line (U937) with recombinant IFN-γ. CXCL10 cDNA has an open reading frame of 1173-bp containing 4 exons and encoding a protein of 98-amino acids. The primary translational product of the CXCL10 gene is a 12 kDa protein containing two internal disulfide cross bridges. CXCL10 exerts its biological effects by binding to CXCR3, a seven trans-membrane-spanning G protein-coupled receptor in a paracrine or autocrine fashion, which is predominantly expressed on activated T, B lymphocyte, natural killer (NK), dendritic and macrophage cells. CXCL10 induction depends predominantly on the carboxyl-terminal region of CXCR3, which is essential for CXCR3 internalization, chemotaxis and calcium mobilization induced by the CXCL10 ligand. The powerful chemotactic action of CXCL10 on activated lymphocytes allows it to modulate both innate and adaptive immunity, inducing tissue damage and modulating tumor formation^[1].