The secret to stopping malaria lies in the liver

Australian scientists have identified a new type of immune cell that stays in the liver, guarding against malaria infection. Their study has been published in the journal Immunity and used to develop a vaccine method which, when tested in mice, gave complete protection against malaria.

Dr Daniel Fernandez-Ruiz, a co-author on the study from the Peter Doherty Institute for Infection and Immunity, explained that once you are bitten by a malaria-carrying mosquito, the parasite quickly makes its way to the liver. “After a few days, the infection progresses into the blood, which causes life-threatening symptoms,” he said.

Liver-resident memory immune cells do not recirculate through the body, but permanently guard the liver where they are ready to fight infections immediately. Dr Fernandez-Ruiz said this makes them particularly effective in fighting against liver-stage malaria “because of their ability to immediately recognise and efficiently kill parasites before they progress to the blood and cause disease”.

In collaboration with researchers from the Monash Biomedicine Discovery Institute and the Centenary Institute, Dr Fernandez-Ruiz and his team used their discovery to develop a ‘prime and trap’ vaccine method that is completed with two injections. The first, a ‘priming’ injection, sets the immune response in motion, boosting the army of malaria-specific immune cells in the body and helping to attract them to the liver. The second ‘trapping’ injection pulls an abundance of these immune cells into the liver and then converts these cells into liver-resident immune cells to permanently guard the liver from malaria infection.

“Once vaccinated, these immune cells trapped in the liver effectively protected against malaria infection,” said Associate Professor Irina Caminschi, a study co-author from the Monash Biomedicine Discovery Institute, who claimed the discovery “opens a new door for the design and development of the most efficient malaria vaccine to date”.