Interleukin (IL)‐2, IL‐4, and Tumor Necrosis Factor‐α Responses duringEntamoeba histolyticaLiver Abscess Development in Gerbils

To determine cytokine production patterns during hepatic amebiasis, gerbils were infected with Entamoeba histolytica in the liver. Then spleen and hepatic lymph node cell proliferation and interleukin (IL)-2 (a Th1 marker), IL-4 (a Th2 marker), and tumor necrosis factor-alpha (TNF-alpha) production in response to concanavalin A and amebic antigen in vitro were quantified. Early abscess development (day 5 after inoculation) coincided with IL-2, IL-4, and low TNF-alpha production and strong lymphoproliferative responses, whereas suppression of IL production and lymphoproliferation occurred during acute disease (day 20). Proliferative responses and IL-2 production increased at days 30 and 60 after inoculation, but IL-4 levels remained low. Animals drug-treated at day 20 after inoculation demonstrated high IL-2 and low IL-4 production and resistance to reinfection. While acute hepatic amebiasis in gerbils is accompanied by transient immunosuppression, late infection and resistance to reinfection are associated with IL-2 production but low IL-4 and TNF-alpha production (Th-1-like response).