Malaria: Prevention by Blocking Cell’s Passage

Researchers at the Wellcome Trust Sanger Institute have discovered an understanding on how the most deadly species of malaria parasite, Plasmodium falciparum, invades human red blood cells.

They used the technique called Avidity-based Extracellular Interaction Screen (AVEXIS), which discovered the interaction between the parasite protein and the host receptor.

The parasite relies on a single receptor on the red blood cell's surface to invade, offering an exciting new focus for vaccine development.

The blood stage of Plasmodium's lifecycle begins when the parasite invades human red blood cells, and it is this stage that is responsible for the symptoms and mortality associated with malaria.

"Our research seems to have revealed an Achilles' heel in the way the parasite invades our red blood cells. It is rewarding to see how our techniques can be used to answer important biological problems and lay the foundations for new therapies," senior co-author Gavin Wright said in a statement.

However, researchers demonstrated that disrupting this interaction completely blocked the parasite from gaining entry into the red blood cell. Importantly, this was true across all parasite strains tested, making it appear that the receptor is a universal entry pathway. It is hoped that the parasite's dependency on this one protein can now be exploited to develop new and effective vaccines.

Malaria kills approximately one million people every year, mostly children under the age of five in sub-Saharan Africa. Researchers have tried for many years to develop a vaccine to prevent the parasite gaining entry into our red blood cells, but so far they have been unsuccessful.

One of the challenges is that the parasite is adaptable - although several red blood cell receptors had been previously identified, none was shown to be essential: when entry through one receptor is prevented, the parasite is able to switch to another. This new research has found a single receptor that is absolutely required by the parasite to invade.

"The discovery of a single receptor that can be targeted to stop the parasite infecting red blood cells offers the hope of a far more effective solution," Investigator at the Jenner Institute, Adrian Hill, said.

According to the Health Protection Agency, malaria is not endemic in the UK, but in the five years between 2006 and 2010, almost 1600 cases have occurred every year on average in travellers returning to or arriving in the UK from malaria-endemic countries.