FIG. 3.

Host cell invasion of gp82-expressing or gp82-deficient T. cruzi isolates. (A) Metacyclic forms of isolates 569, 588, and CL were incubated with HeLa cells for 1 h at 37°C, and the intracellular parasites in at least 500 Giemsa-stained cells were counted. Values are means and standard deviations (SD) of six experiments. (B) Parasites were left untreated or treated for 30 min at room temperature with 500 μg of MAb 3F6 per ml or 250 μg of the corresponding Fab fragments per ml before being added to HeLa cells. After a 1-h incubation, the HeLa cells were washed in PBS and stained with Giemsa. The reference value of 100% was ascribed to the untreated control. Values are means and SD of three experiments.