The involvement of nucleus in the maturation processes of Dengue-2 virus in a mosquito cell line, C6/36 cells, has been identified by the electron microscopy and immunocytochemistry. The C6/36 cells were obtained from ATCC and maintained in MEM culture medium containing 10% fetal bovine serum at 28°C. The cell suspensions or cells grown on teflon-coated coverslips were infected with Dengue-2 virus (107/ml) for various time periods of 2 hours, 3, 6, 8, and 10 days. The cells were then fixed in buffered 1.5% glutaraldehyde, and washed in acetone before immunolabeled with monoclonal antibody. An indirect immunocytochemical labeling method of avidin-biotin complex (ABC) conjugated with peroxidase or gold particles (20 nm in diameter) and a flat embedding technique were used to localize the virus particles.At early stages of infections (before 3 days), there were no virion particles detected. After 6 days and on of infections, cytopathic effect (CPE) was observed and showed positive immuno-peroxidase reactions under the light and electron microscopies.
