NEUTROPHILS PLAY A CRITICAL ROLE IN EARLY RESISTANCE TO AMEBIC LIVER-ABSCESSES IN SEVERE COMBINED IMMUNODEFICIENT MICE

Animal models of liver abscess formation with Entamoeba histolytica su ggest that the neutrophil is the first cell of the host immune system to interact with the invading ameba. In vitro studies have suggested t hat lysis of neutrophils by virulent amebae may exacerbate the damage seen in amebic liver abscesses, To investigate the role of neutrophils in vivo, we used the severe combined immunodeficient (SCID) mouse mod el of amebic liver abscess formation and compared liver damage in neut rophil-depleted and control mice, We found that neutrophil-depleted an imals have significantly larger amebic liver abscesses at early stages of infection and that abscesses in neutrophil-depleted SCID mice lack the prominent inflammatory cell ring seen in amebic liver abscesses i n control SCID mice, These data suggest that neutrophils play a protec tive role in the early host response to amebic infection of the liver.