Lymphotactin is a chemokine-like molecule produced selectively, if not exclusively, by activated CD8+ T cells. Lymphotactin is a C-type member of the chemokine superfamily, but retains only the 2nd and 4th of the four cysteine residues conserved in other chemokines. In normal tissues, lymphotactin is expressed at high levels in spleen, thymus, small intestine, and peripheral blood leukocytes, as well as at low levels in lung, prostate, and ovary. Lymphotactin is chemotactic for CD4+ and CD8+ T cells but not for monocytes, and induces a rise in intracellular calcium in peripheral blood lymphocytes. The specific receptor for lymphotactin is XCR1, a member of the G protein-coupled receptor family.