LONDON, Aug 27 (Reuters) - Scientists have created the first
full map of mosquito immune cells and found a new type of cell
that could have a role in how mosquitos are able to fight off
malaria.
The findings, published in the journal Science, could help
scientists uncover new ways of preventing mosquitos from
spreading the malaria parasite to people and break the chain of
transmission, the researchers said.
Malaria affects more than 200 million people worldwide and
killed an estimated 405,000 people in 2018 - most of them babies
and children under five years old. It is caused
by Plasmodium parasites, which are spread in the bites of
female Anopheles mosquitoes.
"We discovered a rare but important new cell type, which we
called a megacyte, which could be involved in immune priming and
which appears to switch on further immune responses to the
Plasmodium parasite," said Oliver Billker, a molecular infection
expert at Sweden's Umeå University, who co-led the work.
The mosquito immune system controls how the insect can
transmit parasites or viruses, Billker's team explained in the
study, but until now, scientists knew little about the cell
types involved.
The team studied both Anopheles gambiae mosquitos, which
transmit malaria, and Aedes aegypti mosquitos, which carry
viruses that cause other human infectious diseases such as
Dengue fever, Chikungunya and Zika.
They analysed more than 8,500 individual immune cells to see
exactly which genes were switched on in each cell and to
identify molecular markers for each unique cell type.
"Mosquitos appear to have a sweet spot of immunity to
parasites like malaria, with enough immunity to the infection
that it doesn’t kill the mosquito but not enough to remove the
parasite," said Sarah Teichmann, an expert at Britain's Wellcome
Sanger Institute who co-led the study.
(Reporting by Kate Kelland; Editing by Alison Williams)