Recombinant Human XCL2/SCM-1 beta Protein

Human XCL2 (also known as Lymphotactin-2, SCYC2, and SCM-1 beta) is a 10 kDa glycosylated protein in the C chemokine family (1-3). XCL1/Lymphotactin is a closely related chemokine that differs from XCL2 by only two amino acids (aa). Human XCL2 encodes a 114 amino acid aa precursor protein with a 21 aa predicted signal peptide. Members of the C chemokine family lack two (the 1^st and 3^rd) of the four invariant cysteine residues normally found in the CC and CXC chemokines. They also have an extended carboxy terminus (4). XCL1/Lymphotactin which is expressed in activated T cells and NK cells, while certain stimulatory conditions have been shown to induce XCL2 expression in macrophages (5-7). XCL2 and XCL1/Lymphotactin bind and activate the G protein-coupled receptor, XCR1. XCR1 is expressed on dendritic cells, T lymphocytes, and B lymphocytes (8-11). Binding of XCL2 to XCR1 initiates chemotaxic cell migration in dendritic cells as well as in T and B lymphocytes. XCR1 is also expressed on ovarian carcinoma cells and may contribute to cancer cell migration and proliferation in response to XCL2 or XCL1/Lymphotactin (12).