Effective new treatments to fight potentially lethal fungal infections in people with cancer, or those with weakened natural immunity, could be developed by gaining fresh insights into a microbe's multilayer defence mechanisms, a scientific gathering in Scotland was told.
The suggestion presented during the Society for General Microbiology's meeting at Heriot-Watt University in Edinburgh were based on a study by Prof. Neil Gow and his colleagues.
The researchers used mutant forms of the yeast Candida albicans that lacked different parts of the yeast cell wall, and uncovered a three-pronged mechanism by which the body's immune defences attack the invading fungus.
They further said that the yeast's cell wall consists of a skeleton-like structure made up of complex sugars called chitins and glucans, covered by an outer layer of proteins, which are highly decorated with sugars.
The researchers added that the white blood cells that form part of the human immune system have receptors on their surfaces which recognise specific parts of the yeast cell wall, enabling them to fasten on to the invading yeast cells, kill them and then break them down.
However, according to them, some other components in the yeast cell wall can damp down this immune response.
The team further stated that the immune system needs to attack the glucans in the yeast inner cell wall.
They said that in the early stages of infection, when the white blood cells start to digest the outer cell wall of the yeast, the glucans become more exposed, and the immune system is then able to mount a chemical attack on these molecules.
"We need to find out exactly what the body's immune systems detect and what receptors the defence cells have that recognise the yeast's cell wall components. However, fungi are clever enough to develop evasion strategies - so we need to figure what these are too. If we can do this we may be able to stimulate the immune system to work more effectively in killing disease-causing fungi," said Prof. Gow.
"In the longer term we may be able to treat patients with immunotherapy - with agents that stimulate their immunity - as well as with anti-microbial drugs. In addition our work may also lead to new ways to detect fungal infections earlier. Too often the fungus has taken a hold and established itself so well that treatment becomes even more difficult," Prof. Gow added.