DOES THE EOSINOPHIL HAVE A PROTECTIVE ROLE IN AMEBIASIS

While normal human eosinophils are destroyed in vitro by virulent Enta moeba histolytica, notwhistanding the presence of antibodies and compl ement, activated eosinophils promptly destroy the parasite although dy ing also at the end of the process. To study the possible in vivo part icipation of eosinophils in invasive amebiasis, we compared the induct ion of experimental amebic abscess of the liver (AAL) in gerbils (Meri ones unguiculatus) previously made eosinophilic through Toxocara canis antigen injection and in normal control gerbils. After intraportal in oculation of 10(5) ameba trophozoites (6 and 24 hr), the ratio of gerb ils with AAL, as well as the number and size of the microabscesses was comparable in eosinophilic and control gerbils. However at 96 hr the number and size of the microabscesses were significantly smaller (p<0. 05) in eosinophilic gerbils. On the other hand the actuarial AAL survi val curve up to 45 days post-amebic inoculation was significantly (p<0 .05) shifted to the right in controls. These results suggest that anti gen-induced eosinophilia may exert a protective effect against AAL in gerbils.