Entamoeba histolytica, the parasitic amoeba responsible for
amoebiasis, causes approximately 100,000 deaths every year. There is currently no
vaccine against this parasite. We have previously shown that intracecal inoculation of E. histolytica trophozoites leads to chronic and non-healing
cecitis in mice. Entamoeba moshkovskii, a closely related amoeba, also causes
diarrhea and other intestinal disorders in this model. Here, we investigated the effect of
infection followed by drug-cure of these species on the induction of immunity against homologous or heterologous species challenge. Mice were infected with E. histolytica or E. moshkovskii and treated with
metronidazole 14 days later. Re-challenge with E. histolytica or E. moshkovskii was conducted seven or 28 days following confirmation of the clearance of amoebae, and the degree of protection compared to non-exposed control mice was evaluated. We show that primary
infection with these amoebae induces a species-specific immune response which protects against challenge with the homologous, but not a heterologous species. These findings pave the way, therefore, for the identification of novel amoebae
antigens that may become the targets of
vaccines and provide a useful platform to investigate host protective immunity to
Entamoeba infections.