Malaria kills more than 1 million children in sub-Saharan Africa each year, making the disease a priority for the development of a vaccine. However, scientists are still trying to discover which antigen from the causative parasite, Plasmodium falciparum, is the most effective at inducing an immune response, and therefore the most useful for vaccination purposes.
P. falciparum has a complex life cycle and resides in different sexual and asexual forms in the blood and in the liver. Researchers at the Pasteur Institute in France believe that the liver-stage of the life cycle is an ideal target for immunization because it lasts for 5.5 days and is not associated with the pathology of malaria (Nature Medicine, 01 Nov 2000).
Based on the knowledge that people immunized with irradiated sporozoites-the infectious form of the parasite injected in the mosquito's saliva into the bloodstream that take refuge in liver cells-are protected against infection, Perre Druihle and his team identified a sporozoite antigen that elicits a powerful immune response. They found that injection of this antigen, LSA-3, into chimpanzees protected them from infection by sporozoites.
Malaria expert, Stephen Hoffman of the Naval Medical Research Center in Baltimore, explains the potential value of the research in an accompanying News & Views article.
Dr Pierre Druihle
Unite de Parasitologie Biomedicale
28 rue du Dr Roux
Dr. Stephen L. Hoffman
Director, Malaria Program (Code 42)
Naval Medical Research Center
503 Robert Grant Avenue
Silver Spring, Maryland 20910-7500
tel: 301-319-7570/7587 (office)
tel: 301-252-9026 (mobile)
(C) Nature Medicine, press release.
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