Malaria parasite ‘Achilles’ heel’ could pave way for new vaccine

A new vulnerability in the malaria parasite Plasmodium vivax (P. vivax) may pave the way for a groundbreaking vaccine, according to researchers at the University of South Florida. The discovery, published in the journal Immunity, identifies a specific site on the parasite's surface protein, known as circumsporozoite protein (CSP), that antibodies can target to prevent the parasite from invading liver cells.

This could stop the dormant form of the parasite that can cause repeated bouts of malaria months or even years after initial infection.

Dr. Noah Sather, a professor in the global, environmental, and genomic health sciences department at USF, explains that finding a new target for targeting the major surface antigen, CSP, has been a long-standing challenge for malaria research. "Nobody has discovered a new way to target the major surface antigen, CSP, for vivax in over 40 years," says Sather. "This is truly a game-changing, paradigm-shifting discovery."

The research, conducted independently by two teams, identified an inhibitory vaccine epitope on the CSP surface antigen that elicits antibodies capable of blocking the parasite from infecting the host. This is particularly important as around three-quarters of P. vivax transmissions come from relapse infections, not from the initial mosquito bite. By preventing the formation of the dormant form, the vaccine could tackle both disease and transmission.

While the discovery marks a significant step forward in malaria research, both Sather and co-author Dr. John Adams note that eradicating malaria, especially the less-studied P. vivax, remains a long journey. P. vivax, which affects a large portion of the world but has historically received less attention, hides in the liver and can reactivate years later, causing frequent fever and malaria complications. A vaccine based on this new target could provide a powerful tool against this understudied form of malaria.