Researchers from Yale University, US, have developed a serum which reduces infection from malaria in mice and it could aid the regular vaccination.
The new serum works by attacking a protein in the saliva of the mosquitos infected with the malaria parasite rather than the parasite itself.
According to researchers, if this method proves effective in further studies, it could be used to enhance existing vaccines.
A new strategy
Erol Fikrig, chief of the Infectious Diseases Section at Yale School of Medicine and senior author, said: “It’s a new general strategy for a vaccine. Rather than targeting the microbe, we target a mosquito protein that influences the environment where the microbe is transmitted.”
When infected mosquitos bite an animal, they then deposit saliva along with the malaria parasite (plasmodium) in the animal’s skin. It has been unclear to scientists whether the saliva aids or hinders malaria infection.
Fikrig and his colleagues investigated this further by first developing a serum to immunise against extracts of mosquito saliva.
The research team then conducted genetic screens to identify specific proteins in the saliva that the serum recognised.
Following further experimentation, it was found that only one of the proteins, called AgTRIO, contributed to protecting against malaria on its own.
The serum’s protective effect
It was demonstrated that the serum could reduce the level of infection in immunised mice that were bitten by mosquitos. Researchers said that the protective effect of the serum bore out in additional tests with different species of malaria parasites, as well as in human liver cells.
The serum could be used to boost the protective effect of existing malaria vaccines, which are currently 40% effective against some severe forms of the disease.
Fikrig noted, however, that serum is more likely to have an effect in association with a traditional vaccine, instead of it working on its own.
Aiding other mosquito-borne infections
If this vaccine strategy proves to be safe and effective, it could help tackle other mosquito-borne infections, such as those which are caused by Zika and West Nile viruses.
Fikrig concluded: “It’s possible that this model could work with other mosquito-borne viruses, bacteria, or protozoa in this case.”
Source: Yale University