The effect of splenectomy on resistance of mice to Entamoeba histolytica infection

Abstract

The role of the spleen in amoebic infection was examined in mice, using strains selected as being either genetically-susceptible (C57BL/6) or genetically-resistant (A/J) to amoebiasis. Splenectomized and sham-operated animals were inoculated intracaecally with 2.5 X 10(5) polyxenic trophozoites of E. histolytica at 6, 12 and 15 days post-splenectomy. The animals were killed 6 or 12 days after infection and the parasite burden was evaluated. Removal of the spleen in both susceptible and resistant mouse strains rendered these hosts extremely resistant to amoebic infection by this criterion. Gross examination of the caeca of non-splenectomized, genetically-susceptible mice showed numerous ulcers over the mucosal surface when compared to the splenectomized group which had superficial lesions or none. These observations suggest that the spleen plays a suppressive role in early anti-amoebic resistance.

Role of neutrophils in innate resistance to Entamoeba histolytica liver infection in mice

“…Attempts to induce experimental amoebic infection in the mouse have been reported by several authors (Wijesundera 1980, Stern et al 1984, Ghadirian & Kongshavn 1985, Meerovitch & Chadee 1988, Cieslak et al 1992, Ghosh et al 1994, however, the majority of these efforts have been unsuccessful in inducing a well-defined amoebic lesion. Some authors postulate that mice have innate resistance to E. histolytica infection.…”

“…Some authors postulate that mice have innate resistance to E. histolytica infection. At present, only a few studies have been conducted to attempt to identify immunological mechanisms which may confer protection against this parasite in mice (Stern et al 1984, Ghadirian et al 1985, Cieslak et al 1992.…”