Deadly parasite’s missing piece to the infection puzzle found

Melbourne researchers have helped uncover the “key” used by the world’s most deadly malaria parasite to infect human blood cells.

Feeding mosquito with human blood

Melbourne researchers have helped uncover the “key” used by the world’s most deadly malaria parasite to infect human blood cells.

Scientists say the finding from this five-year international research project is the missing puzzle piece needed to develop the first vaccine against the parasite, which that kills more than 500,000 people globally each year.

Walter and Eliza Hall Institute of Medical Research discovered the three proteins that join to allow the Plasmodium falciparum parasite to “unlock” entry into a blood cell and transmit disease.

They then worked with Howard Hughes Medical Institute and a Danish biotech company, using Nobel prize winning new type of 3D imaging called cryo-electron microscopy, which gives researchers a never-before-seen view of molecules.

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A malaria vaccine is a step closer after scientists uncover the “key” used by the world’s most deadly malaria parasite to infect human blood cells.

The microscope took hundreds of thousands of images of the protein structure from different angles, piecing them together to reveal the first high-resolution 3D image of this “key”.

Co-lead researcher Professor Alan Cowman said understanding how the parasite gained entry into the red cell was crucial to designing ways to block that interaction and vaccinate against the potentially deadly disease.

“There are quite a few keys the parasite uses, but some of them are dispensable. But this one, if you don’t have this, you don’t get access into the cell,” Prof Cowman said.

“This is a really important fundamental discovery because if they can’t get into the blood cell, they die.”

Another WEHI team lead by Associate Professor Wai-Hong Tham and Dr Jakub Gruszczyk

published their discovery earlier this year of how another deadly malaria parasite, Plasmodium vivax, gains entry to young red blood cells.

Prof Cowman and his team have started to work with this other WEHI group to make the antibodies human red blood cells produce as their defence to stopping the parasite “key” inserting into the “lock”, which is as an important step on the path to vaccine development.

“Ten years ago 2.5 million died from this parasite each year, so it’s been a big success story to bring that number down to 500,000,” Prof Cowman said.

“But the goal is to eliminate malaria. The only way that’s going to happen is to develop a vaccine, and this is a step towards that.”