Bacteria ‘hijack’ human immune system

Research published today in Royal Society Journal Open Biology presents a major new insight into the way bacteria co-exist with or attack humans.

Traditional treatments of infectious diseases through antibiotics have been one of the greatest success stories in medicine. However, the rapid rise and spread of drug resistance, combined with failure to discover and develop new antibiotics, is a serious problem of growing proportions.

When the human body is under attack from bacteria it releases proteins called cytokines, to prepare for the fight against the invaders. This pro-inflammatory response helps humans to fight off bacterial infections such as meningococcus which causes meningitis and septicaemia.  Until now it was thought the role of cytokines was as communication messengers between our cells to help build up our defences.

An investigation led by a team at the University of Nottingham has revealed that bacteria are ‘hijacking’ the body’s own immune defences by binding and taking up the cytokines, enhancing their gene expressions and changing their own virulent behaviour.  As a result, they make themselves more aggressive and able to withstand our defences and go further to invade our tissues.

This was observed in Neisseria meningitis and E. coli infection models and improves our understanding of the whole mechanism of bacterial infection.

Professor Ala’Aldeen, one of the study authors, comments: “The discovery that the bacterial surface molecules act as gatekeepers and hijack human cytokines to improve their own effectiveness could lead to new preventative or therapeutic strategies against bacterial infections, and could be exploited as alternatives to antibiotics. This discovery will enable us to find ways of dampening down the effects of bacterial attack on our immune system by manipulating their genetics and forcing them to ‘forget’ about invading us, and instead co-exist with us.”