Tacrolimus monohydrate (LCP-Tacro) is a macrolide from the culture broth of a strain of Streptomyces tsukubaensis, binds to FK506 binding protein (FKBP) to form a complex. Tacrolimus inhibits calcineurin phosphatase, which inhibits T-lymphocyte signal transduction and IL-2 transcription. Immunosuppressive properties. It prevents the activation of T-lymphocytes in response to antigenic or mitogenic stimulation in vitro and has strong immunosuppressive activity in vivo.