Salivary gland expression system allows mosquitoes to deliver antibody-inducing antigens, as reported in Insect Molecular Biology.
Japanese researchers have managed to engineer mosquitoes into “flying vaccinators” that could theoretically be used to deliver protein-based vaccines against diseases such as leishmaniasis and malaria through their bite. The team, from the Jichi Medical University in Japan, report on the development of a transgenic mosquito that can express foreign proteins in its saliva.
The authors stress that while the flying vaccinator concept could in theory be used to engineer blood-sucking insects as vaccine carriers against malaria, medical safety issues, concerns about informed consent, and other ethical considerations make it “unlikely that this concept will be developed as a public health measure”. However, they suggest that “salivary gland specific expression of relevant proteins is expected to be a powerful tool for the elucidation of saliva-malaria sporozoite interaction.”
Researchers have postulated for 10 years or so that genetically engineering mosquitoes could be a potential strategy against malaria, explains lead author and associate professor Shigeto Yoshida, Ph.D., and colleagues. “For the past decade it has been postulated that the salivary gland could be the way to gain biological control over this important infectious disease.” A major stumbling block, though, has been the inability to generate transgenic mosquito saliva.
Dr. Yoshida and his group report that they successfully engineered mosquitoes to express the Leishmania vaccine candidate, SP15. When insects expressing SP15 in their saliva were allowed to bite mice repeatedly, the mice generated antibodies against the protein. The research is published in Insect Molecular Biology in a paper titled “Flying Vaccinator; a transgenic mosquito delivers a Leishmania vaccine via blood.”