Copycat fungus deactivates body's response to infection

Fungus can imitate signals from the immune system and prevent our body from responding to infection, scientists have found.

Life-threatening fungal infection is a major killer of people with immune system problems such as blood cancers, HIV infection or following organ transplant.

The study, published in the journal PLoS Pathogens, focused on one of the most dangerous infections for people with HIV/AIDS --Cryptococcus neoformans -- which causes hundreds of thousands of deaths worldwide every year, scientists said in a statement.

Fungi are known to make molecules similar to those of our own immune system, but why fungi make these molecules and what their function is has been a longstanding mystery.

Scientists from the University of Sheffield in the UK, have identified how specific immune signals called prostaglandins, made by fungi, are able to disarm immune cells.

The team found that fungi which are not able to make these signals were less able to grow during infection.

"We've discovered that these immune signals - fungal prostaglandins - deactivate immune cells, preventing them from destroying the infection," , said Simon Johnston, who led the team.

"We found the fungus was activating a normal immune pathway that prevents overstimulation of the immune system, but is essential in stopping infections," said Johnston.

"Opportunistic infections like Cryptococcus -- which normally pose no threat, but are potentially life-threatening in those with weakened immune systems -- are an increasing problem and are often very difficult to treat," he said.