Genetically engineered malaria parasite could expedite vaccine development

Red blood cell infected with malaria parasites (blue)--Courtesy of the National Institute of Allergy and Infectious Diseases

Researchers at the nonprofit Seattle BioMed have developed a weakened version of the malaria parasite that could lay the groundwork for a highly protective vaccine candidate.

While worldwide malaria deaths have fallen by 26% since 2000, new challenges to combating the disease have arisen, including drug resistance in the malaria parasite and insecticide resistance in mosquitoes that carry the disease. Though many malaria vaccines are in development, there is no effective one on the market.

In a study published online in the journal Molecular Therapy, the investigators describe how they engineered their next-generation genetically attenuated parasite (GAP) by removing certain genes of the malaria parasite Plasmodium. The idea is that by deleting these genes, the parasite loses its ability to induce an infection in humans.

Though these GAPs are rendered incapable of multiplying, they are essentially alive, meaning they can stimulate a person's immune system to build up defenses against malaria infection. This vaccine strategy has been used to provide protection against viruses and bacteria, but it's a novel approach in fighting parasites.

"This most recent publication builds on our previous work," said Sebastian Mikolajczak, Seattle BioMed senior scientist, in a statement. "The first generation GAP strain had two genes removed from the malaria parasite, but this new 'triple punch,' developed in collaboration with scientists at the Walter and Eliza Hall Institute in Australia, removes three separate genes associated with the pathogenicity of the parasite, effectively abrogating its ability to establish an infection in humans."

Eventually, the researchers hope to test the attenuated parasite in humans at Seattle BioMed's Malaria Clinical Trials Center.

- read the press release
- see the study abstract