Course of Entamoeba histolytica infection in nude mice.

The course of intestinal infection by Entamoeba histolytica was examined in nu/nu BALB/c mice. Mice were inoculated intracecally with 2.5 X 10(5) polyxenic trophozoites and killed at various times after injection. There was no significant difference in the number of E. histolytica trophozoites recovered in the ceca of nu/+ and T cell-deficient nu/nu mice for the first 25 days after amebic injection. Thirty days following amebic injection the number of trophozoites recovered in the ceca of nu/nu mice was significantly higher than the control mice. Silica treatment increased the growth of parasites in the ceca of nu/nu mice when compared with control groups. These data suggest that both macrophages and T lymphocytes play an important role in host defense against amebic infection in nude mice.