Plasmodium falciparum is responsible for the most severe forms of human malaria. Invasion of host red blood cells is an essential step of the complex life cycle of this parasite. During the process of invasion, P. falciparum, which appears in the stage of a merozoite, is exposed to antibodies from the immune system. Consequently, the proteins of the merozoite that interact with red blood cells are a possible weak point, and thus a very clear target to develop vaccines. Alfred Corts, an ICREA researcher working at IRB Barcelona and an expert in molecular parasitology, together with researchers from the National Institute for Medical Research (NIMR) in London, have discovered that the parasite has the ability to switch on and off the expression of some of the proteins it uses to enter its victims red blood cells. The researchers believe that this ability makes the parasite more adaptable when attempting to invade the cells. The study is published in Fridays issue of Plos Pathogens, the scientific journal with the greatest impact on the field of Parasitology.

30 genes are know to be involved in the process of invasion. Now, the scientists have found that P. falciparum can activate and deactivate the expression of 7 of these genes (and their corresponding proteins) without compromising the parasites ability to enter normal or modified red blood cells. According to Corts, this suggests that the varied expression of these genes may help the parasite to escape the host organisms immune responses, although the researcher points out that this is yet to be confirmed.

The researchers discovered that the silencing mechanism happens at the epigenetic level, meaning that the parasite stops expressing a certain gene without changing the underlying genetic information, and that the mechanism is flexible, adaptable and easily reversible. This means that the parasite can re-express the proteins relatively easily when infecting another individual or silence th
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Contact: Sonia Armengou
armengou@irbbarcelona.org
34-934-037-255
Institute for Research in Biomedicine (IRB)
2-Aug-2007