Malaria is spread by mosquito bite, once injected the parasites migrate to the liver where they mature and then their sporozoites (infective cells) are released into the blood, causing disease and fatal complications.
During the study the researchers genetically modified the proteins essential for sporozoite development, and could weaken these parasites such that they invade liver cells and stimulate an immune response, but don't develop further.
Previous studies have shown how to successfully vaccinate mice using a rodent malaria which had one of these liver stage genes removed, specifically p36p.
The researchers showed the first transition of such a vaccination from the rodent system to humans, by inactivating the equivalent gene (p52) in the major human malaria parasite, P. falciparum. These human parasites are unable to develop in liver cells.
The researchers believe that the findings may open up new pathways for its use as a human vaccine.
The findings are published October 31st in the open-access journal PLoS Pathogens.