protection. A mutation that is common among Papua New Guinea prevents the malaria parasite from infecting red blood cells ( insert ).
The researchers found that a variant gene in humans, common in Papua New Guinea, confers protection against malaria. At the same time, others have shown that the malaria parasite has multiple ways to evade this defense, casting doubt on efforts to find a single vaccine against the disease.
Plasmodium falciparum causes malaria by invading red blood cells, reproducing inside, then break open cells to release a new brood parasites. To enter the parasite corresponds to a protein on the outer membrane in a receptor protein on the surface of the blood cell, like a key in a lock. Researchers knew such a combination lock keys, and last year, several groups have identified a second possible "key" protein, called BAEBL or EBA140. Studies have suggested its corresponding "lock" could be a cellular receptor blood called glycophorin C.
In the January issue of Nature Medicine Alan Cowman parasitology at the Hall Institute of Medical Research Walter and Eliza in Melbourne, Australia, and colleagues demonstrate that EBA140 does indeed bind to glycophorin C. moreover, when they added antibodies to EBA140 to a mixture of noise and red blood cells, antibodies clung the protein, preventing extraneous to their insidious entry.
Cowman notes that the epidemiological work also seems to support a role for EBA140. In Papua New Guinea, an area plagued by malaria, nearly half of the population have a mutated version of glycophorin C, which makes them resistant to disease. The researchers showed that antibodies against EBA140 did not inhibit the entry into cells with glycophorin C mutated parasite, suggesting the parasite can not use EBA140 to lock on the modified receptor.
Meanwhile, the malaria researcher Louis Miller of the National Institute for Allergy and Infectious Diseases in Bethesda, Maryland, and colleagues studied the variation from EBA140 that binds the red blood cell. Parasites in samples from all over the world, they found four slightly different versions of the protein, only one of which binds to glycophorin C; the other three had not yet unknown targets, the team reports in December 2nd number of Journal of Experimental Medicine . Apparently, small changes in protein can lead to whole new ways to penetrate cells, researchers say - which would help the parasite evade mutations such as is common in Papua New Guinea
"the two additional documents. each other very well," says researcher malaria Peter Preiser National Institute for medical research in London. and together, he said, they rush all the hopes for development of a single vaccine that blocks the entry of pests. "There will not be a magic protein you vaccinate with which will solve all the problems of malaria." instead, he said, researchers will discover Plasmodium roads in the cell and to develop combined vaccines.
Related Sites
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Miller's article in Journal of Experimental Medicine
More information on Plasmodium
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