USF researchers’ discovery could advance malaria vaccine development

University of South Florida researchers say they have found a previously unknown weakness in a malaria parasite — a discovery that will help scientists develop a vaccine capable of preventing recurring infections. 

Their findings, published Wednesday in the scientific journal Immunity, focus on the most widespread form of the mosquito-born parasite found outside of sub-Saharan Africa, called Plasmodium vivax. 

That’s the same strand of the parasite that caused an outbreak of seven locally-acquired malaria cases in Sarasota and Manatee counties between May and July 2023, according to the Centers for Disease Control and Prevention. Researchers believe those patients were all infected with the disease within a tight, four-mile radius, the CDC says. All eventually recovered. 

USF researchers identified a site on the parasite’s primary surface protein that can be targeted by antibodies, the university says, which would potentially stop the parasite from being able to invade liver cells and establish its dormant form. 

“We identified a new kind of gap in the armor, so to speak, that nobody knew about,” Noah Sather, a professor in the USF College of Public Health, says in the release. “We found that we can exploit that to prevent the bug from infecting.”

Sather and USF researcher John Adams both led their own research studies into the same strand of the parasite, but from different scientific perspectives. Adams, a parasitologist, studied the parasite and humans’ natural immune responses, while Sather, a vaccine immunologist, examined the same region at a molecular level as a possible vaccine target.

The researchers initially worked independently and did not realize they had zeroed in on the same vulnerability until Sather, who was working at the University of Washington and Seattle Children’s Research Institute at the time, visited the USF College of Public Health last year while considering applying for a job. Sather was hired by USF in February. 

“Together, our data fit together like puzzle pieces to complete a very complicated picture,” Sather says in the release.

After combining their respective research findings, the two discovered a target, known as an epitope, in a certain protein in this form of malaria that is susceptible to antibodies. Once antibodies are introduced, the parasite is unable to infect the liver, potentially preventing both disease and transmission, the university says. 

That’s especially important because relapses account for an estimated three-quarters of P. vivax transmission, Sather says. 

USF’s discovery is just an early step in developing a vaccine, which will likely take several years to complete, the release says. 

“We’re a few developmental steps away from being able to advance this into humans, but the feasibility is already established,” Sather says in the release. “Our next step is to translate this discovery into effective vaccine formulations.”