The blue mould that invades old bread may cause a minor inconvenience to breakfast but the related species Aspergillus fumigatus can invade humans with more serious consequences. Mould invasion, usually in the lungs, is most common in people whose immune system is not working properly, for example after an organ transplant – when the immune system is deliberately dampened – or in people with AIDS. Anti-fungal drugs are ineffective and around two thirds of patients die. Scientists set about understanding this better by creating mutations in the fungal genes and watching the effects. One mutation, in a gene important for making the glue-like sugar chains (pictured) on the mould’s outside surface, was key. Without these sugars the fungus can’t stick to human cells so can’t invade the lungs. And the fungus also becomes more ‘visible’ to our immune system. This insight opens an alternative route for drug development.
Written by Julie Webb
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