A team of researchers, including grantees of the National Institute of Allergy and Infectious Diseases (NIAID), today reported positive results of research on a new, broad-based malaria vaccine. A paper describing their findings appears in the February 16 issue of the Proceedings of the National Academy of Sciences USA.
Health officials have long sought a vaccine to prevent malaria, a disease that affects 300 to 500 million people and kills up to 3 million people worldwide each year. "Improving international health is a high priority of the NIAID, and malaria research is a major area of interest," comments Anthony S. Fauci, M.D., director of the institute. "Although these results are preliminary and the candidate vaccine has yet to be tested in people, its effectiveness in laboratory tests makes it an interesting candidate for further study."
The most severe form of malaria is caused by a microscopic parasite, Plasmodium falciparum, that is transmitted to humans by mosquitoes. The parasite has a complex life cycle. Following injection into the bloodstream, it rapidly travels to the liver where it multiplies. New forms of the parasite are then released into the bloodstream where they invade red blood cells, ultimately destroying them. In their recent paper, a research team directed by Altaf A. Lal, Ph.D., of the U.S. Centers for Disease Control and Prevention (CDC), describes a new candidate vaccine that targets the malaria parasite at several stages of its life cycle.
The scientists combined segments of 21 different P. falciparum proteins to form a single recombinant protein, which they used to immunize rabbits. Each of the 21 segments, or peptides, was selected because it was recognized by the immune systems of people with malaria, as shown in earlier studies. Furthermore, the peptides targeted different branches of the immune system: B cells, helper T cells and cytotoxic T lymphocytes (CTLs).
Laboratory tests showed that the vaccine induc
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Contact: Sam Perdue
sperdue@nih.gov
301-402-1663
NIH/National Institute of Allergy and Infectious Diseases
16-Feb-1999