Molecular methods to control mosquito-borne diseases
Mosquitoes are the most prominent blood-sucking arthropods that infest man and other warm-blooded animals. They are responsible for the transmission of parasites and viruses, causing a wide range of diseases including malaria and West Nile fever. Over the last 45 years, the use of chemical pesticides such as dichlorodiphenyltrichloroethane (DDT) has been the method of choice for mosquito control, while the antimalarial drug chloroquine has limited malaria-associated mortality. However, the detrimental side-effects of pesticides and the emergence of drug-resistant mosquitoes indicate the need for alternative approaches. Measures to control other arthropods such as ticks and mites have relied on the identification and use of concealed antigens as vaccine candidates. In a similar approach, the EU-funded MOSQUITOBLOCK (Integrated biomolecular methods to control mosquito-borne diseases) project wished to identify concealed antigens in various mosquito species and evaluate their potential as vaccine candidates. The ultimate goal was to stop the spread of mosquito-borne diseases on a global scale. Researchers identified proteases responsible for the digestion of protein components found in blood. These included the vitelline membrane protein, early trypsin and chymotrypsin II-like protein precursor found in Aedes aegypti, and the gut esterase 1, sterol carrier protein 2 variant 1, and early trypsin precursor in Culex quinquefasciatus. The proteins early trypsin, vitelline membrane protein and sterol carrier protein 2 variant 1 for both Aedes and Culex were successfully inserted into the bacterial expression system, expressed and purified from E.coli cultures. Purified antigens were used for antibody production and the generated antibodies were validated in vitro for their capacity to inhibit mosquito growth and survival. Overall, the MOSQUITOBLOCK study identified candidate antigens for the development of anti-mosquito vaccines. Considering that mosquito-borne diseases are spread across more than 50 % of the world, an anti-mosquito vaccine would be greatly beneficial with a significantly positive socio-economic impact.
Keywords
Mosquito-borne diseases, antigen, vaccine, MOSQUITOBLOCK, protease