According to the latest news reports, a possible new malaria vaccine with the potential to neutralize all strains of the most deadly species of malaria parasite has been developed by a team led by scientists at the University of Oxford.
The results of this new vaccine independently confirm the utility of a key discovery reported last month from scientists at the Wellcome Trust Sanger Institute who had identified this target within the parasite as a potential game changer that could hold significant promise for vaccine development.
Why a Malaria Vaccine?
According to the World Malaria Report 2010, malaria killed an estimated 781,000 people in 2009, mainly young children and pregnant women. It is caused by parasites that are injected into the bloodstream by infected mosquitoes. And, according to latest World Health Organization data, the parasitic disease killed around 655,000 in 2010. The vast majority of malaria deaths are among children and babies in sub-Saharan Africa.
The most deadly form, Plasmodium falciparum, is responsible for nine out of ten deaths from malaria. Vaccinating against malaria is likely to be the most cost-effective way of protecting populations against disease; however, no licensed vaccine is currently available.
Groundbreaking Technology- The How & Why
In early November, research published in the journal Nature showed that the P. falciparum parasite relies on a single receptor, known as ‘basigin’, on the surface of red blood cells to invade the cell. The parasite attaches a protein – the antigen RH5 – to the receptor, in a sense ‘unlocking’ the doorway for the parasite to enter the red blood cell. Once there, it grows and replicates, causing potentially life-threatening disease.
In a recent paper published in the journal Nature Communications, a team of scientists from the Jenner Institute at the University of Oxford led by Dr Simon Draper, working with colleagues from the Wellcome Trust Sanger Institute and the Kenyan Medical Research Institute-Wellcome Trust Programme in Kilifi, Kenya, demonstrate that a vaccine they have developed induces an antibody response in animal models capable of neutralising all the tested strains of the P. falciparum parasite.
“Our initial finding, reported last month, was unexpected and completely changed the way in which we view how the malaria parasite invades red blood cells,” says Dr Gavin Wright from the Wellcome Trust Sanger Institute, a co-author on both studies. “It revealed what we think is the parasite’s Achilles’ heel in the way it invades our cells and provided a target for potential new vaccines.”
Dr Sandy Douglas, a Wellcome Trust Clinical Research Training Fellow from the University of Oxford and first author on the new study, adds: “We have created a vaccine that confirms the recent discovery relating to the biology of RH5, given it can generate an immune response in animal models capable of neutralising many – and potentially all – strains of the P. falciparum parasite, the deadliest species of malaria parasite. This is an important step towards developing a much-needed vaccine against one of the world’s major killers.”
Scientists have been working for decades on trying to develop an effective vaccine against the disease, but this has proved particularly tricky because the parasites’ antigens – the target of vaccines – tend to be genetically too diverse.
Professor Adrian Hill, a Wellcome Trust Senior Investigator at the University of Oxford, is now hopefull and says, “Our next step will be to begin safety tests of this vaccine. If these prove successful, we could see clinical trials in patients beginning within the next two to three years.”