Using immunocytochemical techniques, we studied the interaction of
antibodies with Entamoeba histolytica trophozoites present during the development of
amebic liver abscess. Hamsters were intrahepatically inoculated with HM1-IMSS axenic amebas and sacrificed at different days post-inoculation.
IgG of rabbit anti-E. histolytica and
IgG of rabbit
anti-IgG of hamster were used, both labeled with
peroxidase. With the rabbit anti-E. histolytica, all trophozoites present in hepatic lesions from 1-7 days post-inoculation were highly labeled. The
IgG of rabbit
anti-IgG of hamster intensively stained only those trophozoites present in lesions from 1-2 days post-inoculation. From day 3, the intensity and number of labeled trophozoites decreased progressively. The results suggest that the interaction between the amebas and the
IgG of hamster is non-specific during the first 2 days. The absence of labeling in the chronic stages could be due to changes in the membrane
antigens of the parasite or to alterations in the bloodstream around
necrosis. Also, the anti-E. histolytica
antibodies produced in the serum during the development of the hepatic disease are apparently incapable of reaching and interacting with the trophozoites present on the
liver abscess. This can explain in part why
antibodies do not have an important role in the defense of the host.