Cell lines from larvae of Aedes (Stegomyia) malayensis Colless and Aedes (S) pseudoscutellaris (Theobald) and their infection with some arboviruses

The establishment of 2 cell lines from first stage larvae of the mosquitoes, Aedes malayensis and Aedes pseudoscutellaris is described. The cells of the A. malayensis line are diploid while those of A. pseudoscutellaris are predominantly polyploid.West Nile and Japanese B encephalitis viruses produced a cytopathic effect (CPE) in the A. malayensis cells. Both these viruses and Dengue-2 virus also produced a cytopathic effect in the A. pseudoscutellaris cells. There was some evidence that the CPE was influenced by the nature of the container. A. malayensis cells of early subcultures grown in Falcon plastic flasks formed large syncytia while those of later subcultures infected under identical conditions produced only small syncytia. Cells of the A. malayensis line grown on glass did not show any cytopathic response in early subcultures, but in cells of higher subcultures grown on glass, the viruses produced a definite CPE presenting as degenerate clumps of cells and floating single cells. It is suggested that the different result is due to continual adaptation of the cells to the culture conditions in the early stages.Cells of the A. pseudoscutellaris line, following infection with viruses formed syncytia, clearly visible on plastic surfaces, but less obvious on glass. An unadapted strain of Dengue-2 in infected human serum produced syncytia in the cells, but did not produce any plaques in a stable line in pig kidney cells. The infected cultures recovered after some days and formed healthy monolayers. Such cells were subcultured without showing any cytopathic response, but continued to produce virus.