Insects have an immune system that allows them to remain asymptomatic when they are infected with a virus that is deadly when transmitted to humans. How is this possible and how does this immune system work? Can we manipulate this immune system and therefore prevent humans from getting infected by insect bites?
The insect antiviral immune response, named RNA interference, is based on the recognition of foreign nucleic acids, very different from what happens in vertebrates where the recognition is mainly based on foreign proteins. The foreign nucleic acid recognized by the insect immune system is viral dsRNA, which is produced for every virus as part of the viral replication cycle. Once recognized, this dsRNA is sliced in tiny dsRNA molecules, loaded in the RNAi machinery and used to further recognized virus molecules 100% identical to the tiny one. Once the tiny molecule finds the target, the later get cleaved, therefore precluding virus replication.
In the fruit fly, virus-infected cells release viral dsRNAs that are subsequently taken up by non-infected cells to launch an antiviral response that will protect them from further infection. This effect is known as systemic immune response. For systemic immunity to functions, dsRNA must enter and « signal » the virus infection to the non-infected cell. How does dsRNA enter drosophila cells?
During my MSCA fellowship I tried to answer these questions by using the fruit fly Drosophila melanogaster as a model insect and an array of drosophila viruses to explore my research.
