Molecular basis of defence against oxidative stress in Entamoeba histolytica and Giardia lamblia.

Gastrointestinal protozoa, viz. Entamoeba histolytica and Giardia, are able to survive in a microaerobic environment. The role of parasitic factors, particularly cysteine, cysteine-rich proteins, superoxide dismutase, and certain alternative mechanisms, has been described in the defence against oxidative stress. The role of the host-derived factors, particularly the phagocytosis of bacteria or host erythrocytes (intact or their enzymatic/non enzymatic components), in the detoxification of reactive oxygen metabolites in E. histolytica may provide novel approaches for the chemotherapy of invasive amoebiasis.