Unlike viruses and bacteria, the Plasmodium genome encompasses more than 6000 genes encoding hundreds of surface antigens,
many of which could serve as vaccine targets. Unlike most pathogens, which display a finite and characteristic set of surface
antigens, Plasmodium varies its antigens, similar to the way human beings change their hair color. Finally, the parasite occurs
in a wide variety of strains, each with its own unique antigenic components.
Experts believe that a successful malaria vaccine must target the two principal forms of the Plasmodium parasite: sporozoites,
the stage present immediately after the mosquito bite, and merozoites, which are released from infected liver cells and cause
typical malaria symptoms such as fever and anemia.
An ideal malaria vaccine must be inexpensive enough to administer to a billion (or more) at-risk individuals, and should be
stable without refrigeration but robust in its ability to treat all strains, including those that may emerge during epidemics
in northern climates.
Mymetics is one of the companies exploring this two-pronged approach, which ideally will induce protection at both stages
by preventing sporozoites from infecting the liver cells where they mature into highly infectious merozoites, and preventing
merozoites from infecting red blood cells where they propagate and cause disease.
With one death every 30 seconds, malaria remains one of humankind's deadliest diseases, which climate change could make even
worse. Regardless of one's position on global warming, a vaccine is our best hope to rid the world of this scourge once and
for all.
Sylvain Fleury is chief scientific officer at Mymetics, European Office, 14, rue de la Colombière, Nyon, Switzerland, tel. +41.21.692.57.75,
sylvain.fleury@mymetics.com
.
Reference
1. M. Pascual et al., "Malaria Resurgence in the East African Highlands: Temperature Trends Revisited," Proceed. of the Nation. Acad. of Scien., 103 (15) 5829–5834 (2006).
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