A team of researchers has discovered the strategy used by a fungus that causes thrush infections and other health problems. The fungus is able to change its cell surface to hide from our immune system. The findings are in a paper that was just published in the journal Nature Microbiology.
Thrush is a fungal infection that normally affects the mouth and throat. Infections are especially common in babies and patients with compromised immune systems. The fungus responsible for these types of infections is called Candida albicans. C. albicans can also cause yeast infections and other medical issues. It’s naturally-occurring in the body but takes advantage of weakened immune systems. In most cases, simple antifungal drugs are enough to treat a C. albicans infection. However, the fungus can be deadly to cancer patients and other people who are severely immunocompromised. Although the fungal infections have been well-studied, scientists still didn’t know exactly how C. albicans was getting around the body’s immune system.
Scientists from the University of Aberdeen, led by an expert from the Aberdeen Fungal Group, investigated the mechanisms that were allowing C. albicans to hide from the human immune system. Generally, the body’s immune system detects the fungus by searching for β-glucan, a molecule found on the fungal cell surface. The research team discovered something interesting, however. When C. albicans is exposed to lactic acid, produced normally in a healthy human body, it changes its own surface chemistry. The fungus changes the composition of its cell surface so as to make it unrecognizable to the immune system. This allows the fungus to stick around, undetected, waiting for an opening such as a temporarily weakened immune system. The fungus essentially hides from the immune system until the immune response is weak enough for it to become pathogenic.
The team’s discovery will aid in the development of better preventative measures and treatments for fungal infections caused by C. albicans. Learning how the fungus invades without immune system detection is a major first step in fully understanding this dangerous organism.
Ballou et al. Lactate signalling regulates fungal β-glucan masking and immune evasion. Nature Microbiology (2016).