Scientists Discover Gene That Protects Against Bacterial Attack

by VR Sreeraman on Oct 30 2008 3:28 PM

A Dutch researcher has unravelled a genetic defence mechanism that combats the lethal bacteria Burkholderia pseudomallei, a bacterium suitable for bioweapons.

The research by Joost Wiersinga from AMC Medical Centre in Amsterdam paves the way for a vaccine against the attack by this bacterium.

It has now been found that B. Pseudomallei, can remain hidden in the human body for many years without being detected by the immune system. The bacteria can suddenly become activated and spread throughout the body, resulting in the patient dying from blood poisoning.

The researchers have now discovered which gene-protein combination makes the lethal bacteria B. pseudomallei harmless.

The researchers focussed their study on the so-called Toll-like receptors, the proteins that initiate the fight against pathogens. There are currently ten known Toll-like receptors which are located on the outside of immune cells, our body’s defence system. The toll-like receptors jointly function as a 10-figure alarm code.

On coming into contact with the immune cell, each bacterium enters its own Toll code, which in turn triggers an alarm in the immune system for known pathogens and activates the defence mechanism.

However, B. pseudomallei still manages to trick the system by entering the code of a harmless bacterium. Thus, the body’s defence system remains on standby.

However, there are people who are resistant, they become infected but not ill. 

The researchers discovered a genetic cause for this resistance, the toll receptor that can fend off B. pseudomallei. It was accomplished by rearing mice DNA in which the gene for Toll2 production was switched on and off. 

''The group where the gene for Toll2 was switched off, survived the bacterial infection. The other receptor that we investigated, Toll4, had no effect - even though for the past ten years medics had regarded this as the most important receptor, said Wiersinga. 

The study, which was mainly aimed at developing a vaccine, has been published in PloS Medicine.