Malaria’s Sticky Secret


A team of Australian researchers have identified a key mechanism that enables malaria-infected red blood cells to stick to the walls of blood vessels and avoid being destroyed by the body’s immune system.

The discovery highlights an important potential new target for anti-malarial drugs.

Malaria kills up to three million people every year, mostly in tropical parts of the world. The disease is spread by mosquitoes that inject victims with microscopic parasites that infect healthy red blood cells.

There are a number of different species of parasite, but the deadliest is the Plasmodium falciparum parasite.

The malaria parasite infects healthy red blood cells, where it reproduces, and producing up to thirty-two new daughter parasites. “It’s like remodelling a house so you can live in it and raise a family,” said researcher Alan Cowman from the Walter and Eliza Hall Institute of Medical Research in Melbourne.

Blood cells infected by the malaria parasite lose their normal rigid shape and develop knobs on their surface, causing them to stick to blood vessel walls and stop circulating smoothly.

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The parasite secretes a ‘glue’, known as PfEMP1, which travels to the surface of the infected red blood cells, leading to the formation of the knobs. The cells become sticky and adhere to the walls of the blood vessels. “This stops the cells from being cleared by the spleen, which is a protective mechanism for the parasite,” Cowman says.

“It’s absolutely essential for the parasite to survive in our bodies.”

Infected cells can also cause blood vessels to clog, a factor in some of the more serious effects of malaria such as cerebral malaria, where the disease affects the brain.

Now, the researchers, led by Cowman, have identified eight new proteins that transport the P falciparum parasite’s ‘glue’ to the surface of the infected red blood cells. They have shown that removing just one of these proteins prevents the infected red blood cells from sticking to the walls of the blood vessels.

“It really is a big step in understanding the parasite itself,” Cowman says. “In the long term it points toward concentrating on some of these proteins so that they don’t work any more, so the parasite would be cleared much more efficiently.”

It is also possible that researchers could use their new understanding to develop weakened forms of the parasite to use in a vaccine against the disease, he says.

Sources: The Times Of India

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