IN-VITRO EFFECT OF RECOMBINANT INTERFERON-GAMMA IN COMBINATION WITH LPS ON AMEBICIDAL ACTIVITY OF MURINE KUPFFER CELLS

The present study examines the role of liver macrophages (Kupffer cell s), of C57BL/6 mice, as effector cells responsible for the killing of Entamoeba histolytica trophozoites in vitro. It was shown that unstimu lated Kupffer cells were inefficient in the killing of E. histolytica trophozoites in vitro. Interferon gamma (IFN-gamma) alone was not able to activate Kupffer cells to amoebicidal state. However, Interferon g amma and lipopolysaccharide (LPS) acted synergistically in this phenom enon. It seems that the acquisition of amoebicidal activity is associa ted with the involvement of hydrogen peroxide, because the addition of catalase partially decreases the killing of this parasite by Kupffer cells. In addition, it appears that the amoebicidal activity of IFN-ga mma-treated Kupffer cells is contact-dependent. Our results indicate t hat the immunologic production of IFN-gamma is important in the activa tion of Kupffer cells for controlling this parasite and that Kupffer c ells are strong effector cells against the amoebae.