NIH and NIAID Find PfSEA-1 Antigen That Protects Against Malaria

The National Institutes of Health (NIH) announced in a press release that it has identified an antigen that can prevent malarial infection. The substance known as PfSEA-1 was found effective in children and adults in malaria-endemic areas. If a vaccine is formulated, it would be a valuable addition to the limited treatments available for malaria. The NIH, in conjunction with the National Institute of Allergy and Infectious Diseases (NIAID) and its grant beneficiaries, have published the results in the May 23, 2014 issue of Science.

The NIH says, “An estimated 627,000 people die from malaria each year according to the World Health Organization, with most deaths from the mosquito-borne parasitic disease occurring among young children living in sub-Saharan Africa.”

PfSEA-1

PfSEA-1 was discovered by scientists at Rhode Island Hospital and Brown University. Professor Jake Kurtis from the Brown University School of Medicine took regular blood samples from 1,000 children living in Tanzania, an area where malaria is common. About six percent of the children living in these areas had natural immunity to malaria. Dr. Kurtis identified malaria parasite proteins only recognized by antibodies in children who were resistant to malaria. In subsequent mice studies, investigators injected a vaccine made from the PfSEA-1 protein, which protected the mice from infection. NIAID scientists continued Dr. Kurtis’ investigations with contributions from Harvard Medical School and the University of Washington.  

PfSEA-1 Study

NIAID scientists conducted a study titled, “Antibodies to PfSEA-1 block parasite egress from RBCs and protect against malaria infection.” Researchers identified Plasmodium falciparum schizont egress antigen-1 (PfSEA-1) using a differential whole-proteome screening method. PfSEA-1 is a parasite antigen expressed in schizont-infected red blood cells (RBCs). The novel agent succeeded in decreasing parasite replication. Scientists used multiple tests to confirm that PfSEA-1 halted malaria infection. Additionally, they found that PfSEA-1 was effective via a unique target, the stage when parasites leave one red blood cell to enter new red blood cells.

Investigators vaccinated five groups of mice to see how the antigen agent performed after the mice had been exposed to malaria. They found that vaccinated mice had lower levels of malaria parasites and they survived longer than unvaccinated mice. Studies in Tanzanian children found no severe infections in the group with PfSEA-1 antibodies. Scientists also found that human males in Kenya with the PfSEA-1 antibodies had 50 percent lower parasite densities than others without the antibodies.