How fungus cripples immune system

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.

Published: 10th February 2019 04:10 PM  |   Last Updated: 10th February 2019 04:10 PM   |  A+A-

Image used for representational purpose only.

By PTI

BERLIN: Scientists have found how a common fungus -- found virtually everywhere on Earth -- can knock out our body's defence system, enabling a potentially fatal infection to develop.

The fungus Aspergillus fumigatus can be found 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, researchers said.

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.

A team led by Oliver Werz of Friedrich Schiller University in Germany, has now discovered how the fungus knocks out the immune defences.

Among other factors, it is gliotoxin -- a potent mycotoxin -- that is responsible for the pathogenicity of Aspergillus fumigatus, according to a study published in the journal Cell Chemical Biology.

"It was known that this substance has an immunosuppressive effect, which means that it weakens the activity of cells of the immune defence system," said Werz.

However, it had not been clear previously how exactly this happens.

Researchers brought immune cells into contact with synthetically produced gliotoxin.

These cells, called neutrophilic granulocytes, represent the first line of the immune defence system.

As soon as such a cell comes into contact with a pathogen, for example a fungus, it releases specific messenger substances into the blood, which attract other immune cells.

Once a sufficiently large number of immune cells has gathered, they can render the intruder harmless, researchers said.

This does not happen if the pathogen Aspergillus fumigatus is involved, researchers said.

The team found that gliotoxin ensures that production of the messenger substance leukotrieneB4 in the neutrophilic granulocytes is inhibited, so that they are unable to send a signal to other immune cells.

This is caused by a specific enzyme (LTA4 hydrolase) being switched off by the mycotoxin.

"This interrupts communication between the immune cells and destroys the defence mechanism.

As a result, it is easy for spores -- in this case the fungus -- that enter the organism to infiltrate tissues or organs," said Werz.

Stay up to date on all the latest Health news with The New Indian Express App. Download now
(Get the news that matters from New Indian Express on WhatsApp. Click this link and hit 'Click to Subscribe'. Follow the instructions after that.)

Comments

Disclaimer : We respect your thoughts and views! But we need to be judicious while moderating your comments. All the comments will be moderated by the newindianexpress.com editorial. Abstain from posting comments that are obscene, defamatory or inflammatory, and do not indulge in personal attacks. Try to avoid outside hyperlinks inside the comment. Help us delete comments that do not follow these guidelines.

The views expressed in comments published on newindianexpress.com are those of the comment writers alone. They do not represent the views or opinions of newindianexpress.com or its staff, nor do they represent the views or opinions of The New Indian Express Group, or any entity of, or affiliated with, The New Indian Express Group. newindianexpress.com reserves the right to take any or all comments down at any time.

flipboard facebook twitter whatsapp