Lymphotactin, also known as XCL1, is member of gamma or C subfamily of chemokines. It is found in high levels in spleen, thymus, intestine and peripheral blood leukocytes, and at lower levels in lung, prostate gland and ovary. The expression of lymphotactin is restricted to activated T cells such as activated CD8+ T cells and other calss IMHC restricted T cells. Since lymphotactin is produced by lymphocytes and acts on lymphocytes, it is speculated that it is a messenger in T cell chemoattraction.