Hunt for malaria vaccine
LOCAL RESEARCHER’S BREAKTHROUGH
A LOCAL researcher is at the forefront of a scientific discovery that could help prevent thousands of deaths annually.
Associate Professor Alyssa Barry, who was recently appointed to lead the Systems Epidemiology of Infection unit within Deakin University’s School of Medicine, worked with the team who narrowed down the proteins and diseasefighting antibodies that could be used to develop a vaccine against the most severe forms of malaria. Prof Barry said the findings were a major step towards developing a viable vaccine for the disease.
Malaria parasites grow within red blood cells, where they insert proteins known as PfEMP1 into the surface, Prof Barry explained.
“As part of their survival strategy within the human host, malaria parasites use PfEMP1 to stick to the walls of blood vessels, and this can cause blockages to blood flow and inflammation, leading to severe disease,” she said.
“Malaria parasites change these proteins to escape from developing immune responses, and every strain has a different set of proteins, making the identification of vaccine targets like finding a needle in a haystack.”
The research team pinpointed which antibodies were most effective in fighting the most severe forms of malaria by using antibody measurements from hundreds of different variants of the proteins.
The team was a collaboration between Prof Barry, the Walter and Eliza Hall Institute of Medical Research (WEHI), James Cook University and malaria experts from Papua New Guinea, France and the US, and Prof Barry was based at the WEHI at the time of the project.
They collected hundreds of PfEMP1 proteins from malaria strains from children in PNG who had been naturally infected by the disease.
“It’s the first time anyone has shown this. For years, researchers have thought that developing a malaria vaccine based on PfEMP1 would be virtually impossible, because the proteins are just so diverse,” Prof Barry said.
“It’s similar to the flu vaccine, where you have to keep adjusting and updating it as the virus strains evolve from year to year. But in malariaendemic areas, children who are repeatedly infected develop immunity to severe malaria by the time they’re about two years old, so we know antimalarial immunity is possible, and it can develop after exposure to only a few strains.”
Prof Barry, who also heads the Translational Genomics Group at the Burnet Institute, said while immunity to milder forms of malaria presented a “formidable obstacle”, immunity to severe malaria targets only a small subset of proteins that have many similarities between strains — making the essential components for a vaccine much easier to identify. The research involved following the children for 16 months and Prof Barry said it was a “long road” involving a large team.
“But it’s a major step forward, and this provides hope that creating a vaccine might be possible,” she said.
There were 219 million cases of malaria worldwide in 2017, leading to an estimated 435,000 deaths, according to the latest World Health Organisation data.