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Malaria’s Invisibility Code Identified

by Medindia Content Team on Dec 29 2005 3:52 PM

Research scholars belonging to the Howard Hughes Medical Institute (HHMI) have discovered how the malaria parasite, Plasmodium falciparum is able to turn on its cloaking genes, and pass the human immune system. Even if the camouflage proteins of the parasite were to be detected by the immune system, the remaining parasites can still escape by switching disguises.

Malaria takes a toll of 2.7 million human lives annually, mostly in Africa. The survival of the parasite is based on its genetic machinery, according to the HHMI research. The gene's promoter which is a DNA sequence initiates the production of its protein, and also keeps under cover the other cloaking genes, according to researchers Brendan Crabb and Alan Cowman. The chief site of action is the promoter, according to them.

The PfEMP1 protein is used by the malaria parasites on the cells which they occupy. The immune system of human beings is evaded by the use of this surface protein. The protein is however incapable of protecting the parasite from immune cells which are on the patrol, making it necessary for the parasite to change its camouflage frequently.

Continuous exposure to malaria is required to gain immunity from it, and by and large children account for the largest number of casualties to the infection. The P. falciparum's 14 chromosomes are where the genes are generally found. The chromosome packaging regulates the var genes, according to the study. The DNA can be encased in chromosomes very securely by certain proteins. The genetic activity takes place at the very edge of the nucleus, wherein the chromosome ends surround the promoter which contain the silenced var genes. The art of cloning big DNA sequences had to be mastered by the scientists for this research.

The parasite’s var genes can be silenced by a promoter. The antigenic variation program has been infiltrated for the first time through this research, and this can also be utilized to find out how immunity from the disease is attained. The var gene machinery is being disassembled by the researchers with the object of identifying the proteins which activate and unpack the promoter region. The final object of the research is to identify new therapies which will counter the immune evasion strategies of the parasite.


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