LONDON – Scientists have created the first complete map of mosquitoes’ immune cells and discovered a new type of cell that could play a role in how mosquitoes fight malaria.
The results, published in the journal Science, could help scientists uncover new ways to prevent mosquitoes from transmitting the malaria parasite to humans and breaking 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 the age of five. It is caused by Plasmodium parasites that spread in the bites of female Anopheles mosquitoes.
“We have discovered a rare but important new cell type, which we called megacyte, which may be involved in immune priming and which appears to turn on further immune responses to the Plasmodium parasite,” said Oliver Billker, expert on molecular infections at Umea University of Sweden who guided the work.
The mosquito immune system controls how the insect can transmit parasites or viruses, said Billker’s team in the study. So far, however, the scientists knew little about the cell types involved.
The team examined both Anopheles gambiae mosquitoes, which transmit malaria, and Aedes aegypti mosquitoes, which carry viruses that cause other human infectious diseases such as dengue, chikungunya, and zika.
They analyzed more than 8,500 individual immune cells to see exactly which genes were turned on in each cell and to identify molecular markers for each individual cell type.
“Mosquitoes seem to have a sweet spot of immunity to parasites like malaria, with sufficient immunity to the infection that won’t kill the mosquito, but not enough to remove the parasite,” said Sarah Teichmann, an expert at Wellcome Sanger, UK Institute co-head of the study.
In 2017, a South Sudanese refugee looked after her baby under a mosquito net in a transit tent in a refugee camp in Uganda. 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. | REUTERS