May 23, 2014 05:30 PM EDT
Scientists Discover Protein That Could Lead To Malaria Vaccine
A protein essential for malaria-causing parasites to escape from inside red blood cells has been discovered, according to a recent study.
The protein researchers from Rhode Island Hospital discovered could lead to the development of a vaccine that would prevent the progression of Plasmodium falciparum malaria, which kills one child every 15 seconds each year in Sub-Saharan Africa and Southeast Asia.
"This research really began in 2002 when our colleagues from the National Institutes of Health, led by Patrick Duffy and Michal Fried, enrolled a birth cohort of children in Tanzania," Jonathan Kurtis, the study's principal investigator and director of the Center for International Health Research at Rhode Island Hospital, said in a statement. "Six years ago we began using these samples to identify novel vaccine candidates and now it's coming full circle. While a portion of this research was conducted in mice, the actual vaccine discovery experiments were performed using human samples, thus we believe the results will effectively translate to humans."
For the study, researchers conducted five independent vaccine trials in which mice were vaccinated with the novel antigen. All mice were then challenged with malaria parasites. In all five experiments, vaccinated mice had lower levels of malaria parasites and survived longer than the unvaccinated mice.
"When my post-doctoral fellow Dipak Raj discovered that antibodies to this protein, PfSEA-1, effectively trapped the malaria-causing parasite within the red blood cells, it was truly a moment of discovery,'" Kurtis said. "Many researchers are trying to find ways to develop a malaria vaccine by preventing the parasite from entering the red blood cell, and here we found a way to block it from leaving the cell once it has entered. If it's trapped in the red blood cell, it can't go anywhere... it can't do any further damage."
Researchers also measured the antibodies to the antigen in the entire Tanzanian birth cohort of 785 children. Surprisingly, among children with the antibodies, there were zero cases of severe malaria. To generalize their results, researchers then went back to a serum bank they had collected from 140 children in Kenya in 1997. They found that individuals with the antibodies had 50 percent lower parasitemia than individuals without these antibodies during a high transmission season.
The findings were recently published in the journal Science.
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