New Delhi, June 8: A team of US researchers, including a Calcutta biologist now back home, has identified a genetic switch that some scientists believe may be used to create mosquitoes resistant to the malaria parasite.
The researchers at the Johns Hopkins University have shown for the first time that a mosquito’s own immune system may be genetically engineered to block transmission of parasites that cause malaria in humans.
“This is proof of principle — a step towards creating super-immune mosquitoes that are able to eliminate malaria parasites,” said Suchismita Das, who was a post-doctoral fellow at the Johns Hopkins lab during the research, and is now assistant professor at the Taradevi Jain College in Calcutta. The findings are published this week in the journal PLoS Pathogens.
The researchers, led by molecular biologist George Dimopolous, activated a gene called Rel2 in the mosquito Anopheles stephensi, enhancing the ability of the insect’s immune system to kill the malaria parasite Plasmodium falciparum in its gut.
“We now know which genes can be manipulated through genetic engineering to create a malaria resistant mosquito,” said Dimopolous, a scientist who has been studying the molecular biology of the Anopheles-Plasmodium interaction for over two decades.
Their laboratory experiments suggest that Rel2 is a genetic switch that activates other genes in the insect that bolster its ability to immunologically eliminate the parasite. “We manipulate molecular components of the (insect’s) immune system to identify the parts necessary to kill the malaria parasite,” Dimopolous said in a statement issued through Johns Hopkins.
Researchers hope that such genetically-engineered mosquitoes when released into the environment will mate with wild mosquitoes and generate offspring that are also resistant to malaria parasites.
But scientists caution that the technology is challenging and controversial.
“This is very good lab science, but it will face enormous challenges before it is ready for the field,” said Purushothaman Jambulingam, a senior scientist at the Vector Control Research Centre, Puducherry, who was not associated with the study. “The viability, feasibility, and safety of such strategies for malaria control have not been established,” Jambulingam told The Telegraph .
“There is significant uncertainty over viability,” said Das, who completed her PhD from Bose Institute, Calcutta, moved to the US for post-doctoral research, and returned to the city in December 2010 with her husband who is a scientist at the Bose Institute.
The malaria-resistant mosquitoes, however, couldn't kill all parasites, and the researchers believe the technology will need to be refined to further improve the immune response of mosquitoes.
For strategies involving genetically-engineered mosquitoes to become effective, such mosquitoes resistant to malaria parasites would have to gradually replace the population of wild mosquitoes, she said.
“It is also unclear whether such a shift in population can actually occur, and how long it might take,” said Das, who’s now teaching molecular biology and microbiology to undergraduate science students.
“I’ve always wanted to be a teacher — and that’s what I’m doing now, and enjoying it,” she said. “But sometimes I do miss the lab environment.”