FTY720 (R)-Phosphate, FTY720 is a novel immune modulator that inhibits lymphocyte emigration from lymphoid organs, which prolongs allograft transplant survival in numerous models. Sphingosine kinases phosphorylate FTYS20 in vivo so that FTYS20 acts as a potent agonist at four of the five sphingosine-1-phosphate (S1P) receptors . FTY720 (R)-phosphate is one stereoisomer of FTY720-phosphate, but it is evidently not formed in vivo. FTY720 (S)-phosphate exhibits Ki values of 2.1, 5.9, 23, and 2.2 nM for S1P1,3,4,5, respectively, while the R isomer binds with 5-130-fold lower affinity.
