Vector Competence of Mosquitoes for Arboviruses

The extreme peroral refractoriness of Aedes aegypti to dengue 2 New Guinea C viral infection can be mollified by using freshly grown virus. Infection rates were increased if mosquitoes were allowed to feed to engorgement on a mixture of concentrated infected cells and infectious supernatant. The infectious supernatants were concentrated approximately 10-fold in CENTRICON filters and this proved to further enhance peroral infection rates. The dose required to infect 50 of the Rockefeller strain of Ae. aegypti, following feeding on a pledget, has now been more accurately estimated to be 10 to the 8th power PFUml ingested. Two monoclonal antibodies to mosquito, Culex tarsalis, mesenteronal brush border proteins have been further characterized. Antibody 13A5.8 has been used in minicolumns to isolate specific antigens from both western equine encephalomyelitis virus susceptible WS and refractory WR mesenteronal brush border fragments BBF. These related antigens are termed R2 refractory and S2 susceptible. Another antibody 32G8 has revealed a relationship between R2 and S2 that suggests posttranslational modification of a nascent R2 protein. 32G8 reacts against the R2 antigen and a small protein fragment, 50-70 kDal, in susceptible mesenterons. Cell culture studies with three strains of Aedes albopictus cells, have revealed that U4.4 and Singh cells are both capable of modulating alphaviral titers.