Kupffer cell functions during intestinal amoebiasis in guinea pigs.

Kupffer cells play an important role in all alimentary tract infections. Their role in intestinal amoebiasis is not clear. Hence, the present study examined Kupffer cell functions--phagocytic capacity and levels of a key lysosomal enzyme, N-acetyl-beta-glucosaminidase -- in guinea pigs infected with Entamoeba histolytica intracaecally. Animals were sacrificed on days 0, 3, 7, 14 and 21 post-infection. During intestinal amoebiasis the phagocytic capacity in Kupffer cells was depressed, whereas lysosomal enzyme levels were highly elevated. Maximum alteration in Kupffer cell functions was observed on the 14th post-infection day (P less than 0.01). Animals which survived until 21 days post-infection did not show any significant (P greater than 0.05) change in their Kupffer cell functions compared with controls and day zero values. Phagocytic capacity was inversely correlated with severity of caecal lesions. In contrast, enzyme levels were directly correlated with degree of caecal lesions. Similar trends were observed in blood monocytes. The depressed phagocytic capacity of mononuclear phagocytes and the increased enzyme release by these cells accompanying intestinal amoebic infection may contribute to the establishment of the infection and the tissue damage that accompanies it.