The parasite that causes malaria lives in the salivary glands of malaria mosquitoes. When the mosquito stings a human for a blood meal, the parasite seized its opportunity to infect humans. Until now, it was not well known how the parasite manages to escape the mosquitoes’ immune system.© Archieffoto AP/EPA/U.S. Centers for Disease Control and Prevention
Wilfred Simons
Leiden
Mosquitoes also have an immune system that tries to fight infections. Until recently, it was a mystery how the malaria parasite manages to live in their host undetected. Researchers at the LUMC now have an idea of how this parasite does this.
Parasitologist Chris Janse of the LUMC discovered that the malaria parasites produce an enzyme that changes proteins on the outside. As a result, the immune cells of mosquitoes no longer recognize the parasite.
That same trick works in people too. As soon as a mosquito bites a person, the parasites make their way into the bloodstream of people. Eventually they settle undetected in the liver, where they multiply.
Janse managed to use genetic modification to create malaria parasites that lack this QC ‘enzyme in disguise’. The mosquito defense system recognized those parasites.
Janse got the idea for his research from cancer researcher Ferenc Scheeren of the Department of Skin Diseases. There are cancer cells with a similar enzyme that perform the same trick in order not to be recognized. Scheeren tipped Janse. “We don’t often see that comparable enzymes arise at two independent moments in evolution.” Janse and his colleagues published their research in the scientific journal PNAS. For Janse this research was a foray; his group focuses on developing a malaria vaccine.