Sphingosine-1-phosphate receptor 1 (S1P1) is one of five high affinity G protein-coupled S1P receptors which mediate a variety of effects including lymphocyte recirculation in the blood.Non-selective S1P receptor agonists, such as FTY720, produce clinical immunosuppression useful for preventing transplant rejection and treating autoimmune diseases. However, they also cause bradycardia by activating S1P3, the receptor responsible for regulation of heart rate.SEW2871 is a selective S1P1 receptor agonist in both human and mouse that is not active at the S1P2-5 receptors. SEW2871, therefore, suppresses the immune response by decreasing the number of lymphocytes circulating in blood without causing bradycardia.