FIG. 3.

Entamoeba histolytica cells adhere to and ingest calcium-treated erythrocytes in a relatively galactose-independent manner. (A) Adherence of E. histolytica to healthy (hatched bars) and calcium-treated (solid bars) erythrocytes. Adherent cells were defined as trophozoites with at least three adherent erythrocytes (means ± SD; n = 6; * indicates a P value of <0.001 compared to healthy cells plus d-mannose; # indicates a P value of <0.01 compared to healthy cells plus d-galactose). (B) Phagocytosis of healthy (hatched bars) or calcium-treated (solid bars) erythrocytes by amebae (reported according to the phagocytic index, i.e., the average number of erythrocytes ingested multiplied by the percentage of amebae positive for ingestion). Following calcium treatment (2.5 mM), erythrocytes were stained with TAMRA and then spun onto amebae and incubated at 37°C for 15 min at a 10:1 erythrocyte-to-ameba ratio. Unengulfed erythrocytes were lysed in water, and amebae containing ingested erythrocytes were counted by microscopy. Data are reported as means ± SD. P values were determined by a two-tailed t test for healthy and calcium-treated cells (* indicates a P value of <0.001 compared to healthy erythrocytes with d-mannose; # indicates a P value of <0.01 compared to healthy erythrocytes with d-galactose; n = 6).