Ascomycin, also called Immunomycin, FR-900520, FK520, is an ethyl

Ethyl group

In chemistry, an ethyl group is an alkyl substituent derived from ethane . It has the formula -C2H5 and is very often abbreviated -Et.Ethylation is the formation of a compound by introduction of the ethyl functional group, C2H5....

 analog of tacrolimus

Tacrolimus

Tacrolimus is an immunosuppressive drug that is mainly used after allogeneic organ transplant to reduce the activity of the patient's immune system and so lower the risk of organ rejection...

 (FK506) with strong immunosuppressant properties. It can be used to treat autoimmune diseases and skin diseases, and can help prevent rejection after an organ transplant

Organ transplant

Organ transplantation is the moving of an organ from one body to another or from a donor site on the patient's own body, for the purpose of replacing the recipient's damaged or absent organ. The emerging field of regenerative medicine is allowing scientists and engineers to create organs to be...

.

Ascomycin acts by binding to immunophilins

Immunophilins

In molecular biology, immunophilins are endogenous cytosolic peptidyl-prolyl isomerases that interconvert between the cis and trans positions.Immunophilins are targeted by immunosuppressive drugs such as rapamycin, ciclosporin, and tacrolimus...

, especially macrophilin-12. It appears that Ascomycin inhibits the production of Th1 (interferon- and IL-2) and Th2 (IL-4 and IL-10) cytokine

Cytokine

Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...

s. Additionally, ascomycin preferentially inhibits the activation of mast cells, an important cellular component of the atopic response. Ascomycin produces a more selective immunomodulatory

Immunomodulator

An immunomodulator, also known as an immunotherapy is a substance which has an effect on the immune system.- Immunosuppressants :Inhibits immune response in organ transplantation and autoimmune diseases.- Immunostimulants :...

 effect in that it inhibits the elicitation phase of allergic contact dermatitis

Allergic contact dermatitis

Allergic contact dermatitis is a form of contact dermatitis that is the manifestation of an allergic response caused by contact with a substance....

 but does not impair the primary immune response when administered systemically.

Ascomycin is produced by the fermentation

Fermentation (biochemistry)

Fermentation is the process of extracting energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound. In contrast, respiration is where electrons are donated to an exogenous electron acceptor, such as oxygen,...

 of Streptomyces

Streptomyces

Streptomyces is the largest genus of Actinobacteria and the type genus of the family Streptomycetaceae. Over 500 species of Streptomyces bacteria have been described. As with the other Actinobacteria, streptomycetes are gram-positive, and have genomes with high guanine and cytosine content...

hygroscopicus.

External links

• Exciting New Eczema Treatment Expected This Year By Jane Schwanke, WebMD Medical News March 17, 2000 (San Francisco)