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Malaria's genetic tricks exposed

Red blood cells

The malaria parasite evades the host's immune system by depositing a protein on the red blood cell's surface. Now researchers have looked at the genes behind this (Image: iStockphoto)

The malaria parasite uses a genetic game of hide-and-seek to attack the body, two new studies show.

Both studies, which are published in the latest issue of the journal Cell, show how the parasite Plasmodium falciparum disguises itself to avoid detection by the human immune system.

Scientists have known since the mid-1990s that the malaria parasite hides from the immune system by depositing a protein on the surface of infected red blood cells.

This effectively makes the parasite invisible to the body's disease-fighting mechanism.

Scientists say that if they know more about the genes that code for this crucial protein, that may lead to new drugs against malaria.

Now a six-year research project led by scientists at Australia's Walter and Eliza Hall Institute of Medical Research in Melbourne has uncovered more details of how the parasite's masking system works.

The researchers found that the parasite uses 60 different protein-masking systems in a deadly game of hide-and-seek.

As soon as the immune system learns to recognise one protein and starts making antibodies against it, the bug switches to another form of the protein.

Wrapped in bundles

Team leader Professor Alan Cowman says while the parasite uses one mask, known as a var gene, it keeps the other 59 invisible to the human body's immune system by wrapping them in bundles.

After a certain time, the parasite silences the active masking gene and randomly chooses another from the bundles to express on its surface, so preserving its disguise.


Cowman says researchers still have a lot of work to do to better understand exactly how the var genes are activated so that drugs could be developed to interfere with the process.

French and Mexican researchers publish related work in the same issue of the Cell.

A commentary in the same issue of the journal says this, together with the Australian research, is "the first solid evidence" of how var gene expression is crucial to the malarial parasite's success at invading its host.

Tags: health, biology, cloning-and-dna