Three strains of type 2 dengue virus (DV-2), which had been isolated from patients exhibiting different disease severity, were inoculated to primary culture of human peripheral blood leukocytes from 3 healthy donors. The percentage of dengue antigen positive cells was highest for the strain isolated from a case of dengue shock syndrome, followed by the strain isolated from a case of dengue hemorrhagic fever, and lowest for the strain isolated from a mild case of dengue fever (DF). Generally, similar trend was observed for the amount of some cytokines released into infected culture supernatant, such as interleukin 6, and tumor necrosis factor-alpha. However, such a trend was not observed for interleukin 1 beta.