Human Neutrophils Activated by Interferon-γ and Tumour Necrosis Factor-α Kill Entamoeba histolytica Trophozoites In Vitro

Abstract

The interaction between cytokine-activated human neutrophils and Entamoeba histolytica trophozoites was studied as well as the mechanism(s) involved. Treatment of neutrophils with rlFN-γ alone allowed them to kill 30% of E. histolytica trophozoites; however, rlFN-γ and rTNF-α pretreatments in combination increased neutrophil killing to 70%. In the absence of direct contact between neutrophils and amebae, rlFN-γ-treated neutrophils were shown to kill 70% of amebae, and rlFN-γ- and rTNF-α-treated neutrophils killed 97% of amebae. Neutrophil enhancement of amebicidal activity following cytokine treatments was correlated with Increased neutrophil resistance to amebic contact-dependent killing and was shown to be 73% H₂O₂ dependent.

amebae, cytokines, oxidative killing, neutrophils, TNF