FRIDAY, SEPTEMBER 30, 2016

New malaria discovery may lead to better vaccine and treatment

Washington University School of Medicine said on Thursday that researchers have discovered how a form of malaria common in India, Southeast Asia and South America attacks blood cells.


The strain, Plasmodium vivax, attacks human red bloods cells by clamping down on the blood cells with a pair of proteins. The new information will help researchers develop better vaccines and treatments.


"More people live at risk of infection by this strain of malaria than any other," Niraj Tolia, an assistant professor of molecular microbiology and of biochemistry and molecular biophysics, said. "We now are using what we have learned to create vaccines tailored to stop the infectious process by preventing the parasite from attaching to red blood cells."


The World Health Organization reported more than 200 million cases of malaria in 2012. It said that P. vivax is able to hide in the liver and re-emerge years after initial infection. This makes the strain harder to prevent, diagnose and treat.


Previous studies led researchers to believe the strain used one protein to bind to the blood cells. The new study revealed the strain uses a two-step binding process which clamps the cell like tongs.


"It's a very intricate and chemically strong interaction that was not easily understood before," Tolia said. "We have had hints that other forms of malaria, including the African strain, may be binding in a similar fashion to host cells, but this is one of the first definitive proofs of this kind of attack."


Tolia said blocking any of the proteins with drugs or vaccines would stop the process.


"For example, some people have a mutation that eliminates the protein on red blood cell surfaces that P. vivax binds to, and they tend to be resistant to the parasite," Tolia said. "This is why this strain isn't prevalent in Africa - evolutionary pressure has caused most of the populations there to stop making this protein."