Plasmodium antibodies

Research Suggests New Vaccine Candidates for Malaria

Researchers have shown that higher levels of Plasmodium antibodies are protective against severe malaria in children living in Papua New Guinea. Children who have higher levels of antibodies to a specific short amino acid sequence in the malaria parasite, P. falciparum, have much lower rates of clinical and severe malaria. This amino acid sequence, an antigen, is similar among Plasmodium falciparum strains elsewhere in the world, suggesting that this antigen would make a good target for a malaria vaccine. The research is published in Infection and Immunity, a journal of the American Society for Microbiology.

This work demonstrates that individuals lacking immunity to the malaria parasite are prone to experiencing malaria symptoms. These individuals can be identified by their relative deficiency in Plasmodium antibodies to this antigen, as stated by corresponding author Alyssa Barry.

That amino acid sequence, known among scientists as the ICAM1 binding motif, is critical to the virulence of the malaria parasite because it can bind to the tiniest blood vessels in the brain, known as the microvasculature. There the parasite remains hidden from the host’s immune system, causing a severe case of cerebral malaria by blocking the blood vessels and causing inflammation. The ICAM1-binding motif can vary slightly in sequence and still bind tightly, and it is a strong candidate for a vaccine target.

In the study, the investigators measured Plasmodium antibodies responses to the ICAM1-binding motif. The subjects of this study were 187 children ages 1-3, from Papua New Guinea. Once the measurements were taken, the investigators followed the children for 16 months to determine the incidence of malaria over time.

Antibody responses, specifically to the ICAM1-binding motif, were associated with a 37 percent lower risk of high-density clinical malaria during follow-up. Children experiencing severe malaria cases had notably reduced levels of Plasmodium antibodies to these sequences.

Globally, more than 200 million cases of malaria occur annually, and the disease kills an estimated 400,000 annually, according to the report. Children are hardest hit.


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