Ascomycin,
also called Immunomycin, FR-900520, FK520, is an ethyl analog of
tacrolimus (FK506) with strong immunosuppressant properties.
Ascomycin
acts by binding to immunophilins, especially macrophilin-12. It
appears that Ascomycin inhibits the production of Th1 (interferon-
and IL-2) and Th2 (IL-4 and IL-10) cytokines. Additionally,
ascomycin preferentially inhibits the activation of mast cells, an
important cellular component of the atopic response. Ascomycin
produces a more selective immunomodulatory effect in that it
inhibits the elicitation phase of allergic contact dermatitis but
does not impair the primary immune response when administered
systemically.
Ascomycin
is produced by the fermentation of Streptomyces hygroscopicus. |