The fungus Aspergillus fumigatus occurs virtually everywhere on Earth, as a dark grey, wrinkled cushion on damp walls or in microscopically small spores that blow through the air and cling to wallpaper, mattresses and floors. Healthy people usually have no problem if spores find their way into their body, as their immune defence system will put the spores out of action. However, the fungus can threaten the lives of people with a compromised immune system, such as AIDS patients or people who are immunosuppressed following an organ transplantation.

An international research team led by Prof. Oliver Werz of Friedrich Schiller University, Jena, has now discovered how the fungus knocks out the immune defences, enabling a potentially fatal fungal infection to develop. Among other factors, it is gliotoxin -- a potent mycotoxin -- that is responsible for the pathogenicity of Aspergillus fumigatus. "It was known," says study manager Werz of the Institute of Pharmacy at the University of Jena, "that this substance has an immunosuppressive effect, which means that it weakens the activity of cells of the immune defence system." However, it had not been clear previously how exactly this happens. Werz and his team colleagues have now studied this in detail and have clarified the underlying molecular mechanisms.

To achieve this, the researchers brought immune cells into contact with synthetically produced gliotoxin. These cells, called neutrophilic granulocytes, represent the first line of the immune defence system.

See: Gliotoxin from Aspergillus fumigatus Abrogates Leukotriene B4 Formation through Inhibition of Leukotriene A4 Hydrolase. Cell Chemical Biology
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology