RESUMO
The unlabelled immunoperoxidase, peroxidase-anti-peroxidase (PAP), technique was used to detect dengue type-2 viral antigen in several cell systems including the endogenous peroxidase containing cells. These cells are the mosquito cell line (C6/36), continuous cell line of rhesus monkey kidney (LLC-MK2), human monocyte culture both cell suspension and monolayer, and human peripheral blood leukocytes. All of these specimens gave the same results that dengue-2 viral antigen presented in cytoplasm only and the patterns of marker presentation in positive cells varied depending on the duration after infection. The sensitivity of this method is extremely high since it can detect dengue-2 antigen after its attachment on mosquito cells (15 min) as seen in experiments with mosquito cell line, C6/36. False positive was not observed in all cell systems tested.