New Threat from Bite of Common Bloodsucking Insect Named

Mosquito Suppresses Human Immunity

Mosquito saliva is known to play an important role in the transmission of viruses such as yellow fever, Zika, dengue and chikungunya, but many of its functions remain to be understood. In a new study, scientists have found that a protein in mosquito saliva interacts with a human immune molecule, promoting infection of human skin caused by a transmitted virus.

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«Ticks and mosquitoes don't just carry pathogens,» explains virologist Erol Fikrig. «Their saliva serves multiple purposes when it interacts with the human host.»

To conduct the analysis, the team screened the yeast library of human protein displays with Nest1, a protein in Aedes aegypti mosquito saliva that they had identified as important in previous studies.

The scientists demonstrated that Nest1 interacts with human CD47, an immune receptor found on the surface of many cells in the body. CD47 controls several immune processes, including those that protect certain cells and destroy others.

«This interaction shows that the mosquito is trying to change the biological functions controlled by CD47, — Alejandro Marin Lopez reports. — We saw that Nest1 suppresses some of these functions, such as phagocytosis, immune cell migration, and inflammatory response. These changes promote increased viral replication in the skin.

The new discovery expands knowledge of how disease vectors, such as mosquitoes, and hosts, such as humans, interact, and the findings could lead to the development of treatments. which will help prevent mosquito-borne diseases.

The mosquito protein binds to CD47 approximately 25-50 times stronger than the ligand that normally binds to CD47. According to experts, this may have implications for the treatment of various other diseases.

«The interaction between CD47 and SIRPA has been studied for many years, and based on this interaction, drugs are being developed to prevent cancer and atherosclerosis, — concludes Fikrig. — It is possible that this mosquito protein, which is superior to SIRPA, could lead to new and better treatments for these and other diseases.»