ROLE OF THE ENTAMOEBA-HISTOLYTICA CYSTEINE PROTEINASE IN AMEBIC LIVER-ABSCESS FORMATION IN SEVERE COMBINED IMMUNODEFICIENT MICE

Evidence from in vitro studies suggest that the Entamoeba histolytica cysteine proteinase plays a role in the tissue lysis and cytopathic ef fects seen in invasive amebiasis, We used affinity-purified antibodies against a recombinant E. histolytica cysteine proteinase to demonstra te that the proteinase is present extracellularly in amebic liver absc esses in mice with severe combined immunodeficiency (SCID mice). Treat ment of E. histolytica trophozoites with specific cysteine proteinase inhibitor E-64 blocked or greatly reduced liver abscess formation at 4 8 h in SCID mice, Our study suggests an important role for a functiona l cysteine proteinase in amebic liver abscess formation.