STRL22 Is a Receptor for the CC Chemokine MIP-3α☆☆☆

Abstract STRL22 is a human seven transmembrane domain orphan receptor related to known chemokine receptors and expressed in peripheral blood lymphocytes, tumor infiltrating lymphocytes and lymphoid tissues. MIP-3α/LARC/Exodus is a CC chemokine that is chemotactic for lymphocytes and that is expressed in activated cells, including monocytes, T cells, endothelial cells, and fibroblasts, and in liver, lung, and some lymphoid tissues. We report here that STRL22 -transfected human embryonic kidney 293 cells demonstrated specific binding for MIP-3α and that MIP-3α, but no other chemokines, produced a calcium flux in the STRL22 -transfected cells. We show that MIP-3α, unlike other chemokines, produced a calcium flux in freshly-isolated peripheral blood lymphocytes and we show that MIP-3α also produced a signal in tumor infiltrating lymphocytes that express STRL22. Since STRL22 is the sixth functional CC chemokine receptor identified, it should be re-named CCR6.