DEVELOPMENT OF AMEBICIDAL CELL-MEDIATED-IMMUNITY IN GERBILS (MERIONES-UNGUICULATUS) IMMUNIZED WITH THE GALACTOSE-INHIBITABLE ADHERENCE LECTIN OF ENTAMOEBA-HISTOLYTICA

The galactose-inhibitable adherence lectin of Entamoeba histolytica is a protective antigen in the gerbil model of amebic liver abscess. To further understand the mechanisms of vaccine efficacy, we studied the cell-mediated immune response to the lectin in gerbils. Splenocytes harvested from immunized gerbils demonstrated in vitro proliferation and production of interleukin-2 and gamma-interferon in response to purified adherence lectin (P < 0.05 for each compared to control splenocytes). Splenocytes from immunized gerbils developed direct amebicidal activity (P = 0.014) following in vitro stimulation with the adherence lectin. Splenocytes harvested from immunized gerbils following intrahepatic challenge with viable E. histolytica trophozoites demonstrated proliferative and amebicidal responses (P < 0.05). In conclusion, immunization with the E. histolytica galactose-inhibitable adherence lectin elicits an amebicidal cell-mediated response that is enhanced by parasite challenge.