Scientists have identified an antigen, PfSEA-1, that generates antibodies hindering the ability of malaria parasites to multiply. Results of this research are published in the journal Science.
PfSEA-1 was linked to reduced parasite levels among children and adults in malaria-endemic areas. Mice that were exposed to this antigen in an investigational vaccine also demonstrated lower malaria parasite levels. PfSEA-1 was identified in plasmas samples from 2-year-old Tanzania children who were either resistant or susceptible to malaria infection. Testing confirmed that antibodies to PfSEA-1 stopped malaria infection at the point when parasite leaves one red blood cell to invade a new one. Previous vaccine candidates have tried to block the stage when parasites enter the red blood cells.
Five groups of mice with the novel antigen were vaccinated to assess its effects after the mice were exposed to malaria. Across all 5 groups, vaccinated mice had lower levels of malaria parasites and lived longer than the unvaccinated mice. Scientists also evaluated plasma samples from 138 males ages 12–35 years living in a malaria-endemic area of Kenya and found that those with detectable PfSEA-1 antibodies had 50% lower parasite densities compared to individuals with no detectable antibodies.
The research supports PfSEA-1 as a potential vaccine candidate that could work alone or in combination with other vaccines targeting different stages of malaria infection.
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