PI4KIII beta inhibitor 3 is a PI4KIII inhibitor, has an IC50 of 5.7 nM. PI4KIII beta inhibitor 3 exerts significant immunosuppressive activity, with IC50 value of 3 nM in the mixed lymphocyte reaction (MLR) assay. PI4KIII beta inhibitor 3 inhibits IL2 and IFNy secretion with IC50 values of less than InM in each case. Thus, PI4KIII beta inhibitor 3 is shown to be as effective at inhibiting IL2 and IFNy secretion as conventional immunosuppressants such as cyclosporine A. IC50 on IFNy and IL-2 release of Cyclosporine A are 2nM and less than 1 nM respectively[1].

Oral administration of PI4KIII beta inhibitor 3 results in prolonged graft survival in 3 out of 6 grafts in each group at day 30. Several grafts continued beating after withdrawal of the treatment (up to 60 days), indicating the induction of a certain type of graft tolerance. To evaluate the operational tolerance phenotype, animals with functional graft at day 60 are challenged with a second graft from the same donor strain or from a third party.