Articles > Mounting A Multi-Layered Attack On Fungal Infections

Mounting A Multi-Layered Attack On Fungal Infections

Unravelling a microbe’s multilayer defence mechanisms could lead to
effective new treatments for potentially lethal fungal infections in
cancer patients and others whose natural immunity is weakened.

Although not as well known as bacterial infections, such as MRSA and E.coli,
fungal infections such as that caused by the yeast Candida albicans
can be more serious and lead to a higher death rate. Using mutant forms
of the C. albicans yeast which lacked different parts of the
yeast cell wall, Professor Neil Gow and his colleagues have uncovered a
three-pronged mechanism by which the body’s immune defences attack the
invading fungus.

Presenting the work at the Society for General Microbiology’s meeting
at Heriot-Watt University, Edinburgh, Professor Gow explained 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 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 other components in the yeast cell wall were found
that can damp down this immune response.

In addition, the immune system needs to attack the glucans in the
yeast inner cell wall. 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; 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 Professor 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".

Source : Society for General Microbiology

 


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