Inoculation of Dengue Virus into Nude Mice

Abstract

When athymic nude (nu/nu) and heterozygous littermate (nu/+) mice were injected i.p. with a mouse-adapted strain of dengue virus (DV), differences were noted in the course of infection. The average survival time of nu/nu mice was longer than that of nu/+ mice, although the mortality ratios were not significantly different. DV persisted in some nu/nu mice for long times without exhibiting any symptoms but the mice died after prolonged incubation periods. These aspects were not observed in the nu/+ mice. Infected nu/nu mice produced IgM antibody only transiently in the early stage of infection but did not subsequently show regular IgG antibody production which normally occurred in nu/+ mice. Piamatral and perivascular mononculear cell infiltration in the infected brain was more intense in nu/+ than in nu/nu mice. The course of DV infection in mice may be affected by the availability of T cells. Infectious virus was detected in various organs and tissues of infected mice. The hearts of nu/nu mice tended to show higher virus titers than those of nu/+ mice; the virus concentrations in the brain, skeletal muscle and lymph node were the same in both groups of mice. Specific DV antigen was revealed by the fluorescent antibody technique in cells located in the infected tissues.