XCL1 induces its chemotactic function by binding to a chemokine receptor called XCR1. XCL1 is expressed on macrophages, fibroblasts, and specific lymphocytes.
In humans, XCL1 is closely related to another chemokine called XCL2, whose gene is found at the same locus on chromosome 1. Both of these chemokines share many genetic and functional similarities; however XCL2 has only been known to be observed in humans and not in mice.