PROTECTION AGAINST AMEBIC LIVER-ABSCESS FORMATION IN THE SEVERE COMBINED IMMUNODEFICIENT MOUSE BY HUMAN ANTI-AMEBIC ANTIBODIES

We have used serum from patients with amebic liver abscess to investig ate the role of antibody in the prevention of invasive amebiasis using the severe combined immunodeficient (SCID) mouse model of Entamoeba h istolytica infection. The SCID mice were passively immunized with seru m or purified antibody from patients with amebic liver abscess 24 hr p rior to the direct intrahepatic challenge with 10(6) virulent E. histo lytica trophozoites. This treatment reduced the mean abscess size in t hese animals from 24.5% to 3.5% (P < 0.0001). These results demonstrat e that human anti-amebic antibodies are capable of exerting a protecti ve effect in an animal model of amebic liver abscess formation.