Chemotactic activity for lymphocytes but not for monocytes or neutrophils. In thymus, mediates medullary accumulation of thymic dendritic cells and contributes to regulatoy T cell development, playing a role in self-tolerance establishment. Highest level in spleen, lower in peripheral leukocytes and very low levels in lung, colon and small intestine. Belongs to the intercrine gamma family. XCL1 entry