[Immunosuppressive activity of a microbial product]

Area of Science:

• Microbiology and Immunology
• Natural Product Chemistry
• Pharmacology

Context:

• Microbial products exhibit diverse chemical structures and biological activities.
• The discovery of FK506 (Tacrolimus) highlights the therapeutic potential of microbial compounds.
• Research programs focus on identifying specific inhibitors of interleukin-2 (IL-2) production from microbial sources.

Purpose:

• To discover novel microbial products with immunosuppressive properties.
• To isolate and characterize a new immunosuppressant, FK506, from Streptomyces tsukubaensis.
• To evaluate the efficacy of FK506 in inhibiting T cell-mediated immune responses.

Summary:

• FK506, a novel 23-membered macrolide lactone, was isolated from Streptomyces tsukubaensis No.9993.
• This compound demonstrated potent inhibition of lymphocyte proliferation and T cell-associated immune reactions in vitro.
• FK506 exhibited stronger immunosuppressive effects than cyclosporin in both in vitro and in vivo models.

Impact:

• FK506's profound immunosuppressive properties led to its exploration in organ transplantation models.
• Clinical trials initiated in 1989 demonstrated its potential in various transplantations globally.
• Commercialized in 1993 for liver transplant rejection prevention, FK506 is also investigated for autoimmune disease treatment.