A study led by Johns Hopkins Bloomberg School of Public Health researchers found that injecting a vaccine-like compound into mice was effective in protecting them from malaria. The findings suggest a potential new path toward the elusive goal of malaria immunization.
Mice, injected with a virus genetically altered to help the rodents create an antibody designed to fight the malaria parasite, produced high levels of the anti-malaria antibody. The approach, known as Vector immunoprophylaxis, or VIP, has shown promise in HIV studies but has never been tested with malaria, for which no licensed vaccine exists. A report on the research appears online August 11 in the Proceedings of the National Academy of Sciences (PNAS).
Malaria is one of the world’s deadliest infectious diseases, killing as many as one million people per year, the majority of them children in Africa. Malaria patients get the disease from infected mosquitoes. Of the four types of malaria that affect humans, the parasite Plasmodium falciparum is the most lethal, responsible for the majority of malaria cases. Antimalarial treatments and mosquito habitat modification have contributed to a decline in malaria mortality. But the number of cases remains high, and stemming them is a top global health priority.
In their study, researchers used a virus containing genes that were encoded to produce an antibody targeted to inhibit P. falciparum infection. Up to 70 percent of the mice injected with the VIP were protected from malaria-infected mosquito bites. In a subset of mice that produced higher levels of serum antibodies, the protection was 100 percent. The mice were tested a year after receiving a single injection of the virus and were shown to still produce high levels of the protective antibody.
“We need better ways to fight malaria and our research suggests this could be a promising approach,” notes study leader Dr. Gary Ketner, a professor in the department of microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health.