Fig. 4

Intracellular replication of T. cruzi. a HeLa cells were incubated for 1 h with the indicated parasite strains in D10 or in PBS⁺⁺. After fixation and Giemsa staining, the number of intracellular parasites was counted in a total of 250 cells. Values are the means ± SD of three independent assays performed in duplicate. The invasion rate of strain 515 MT was significantly higher in PBS⁺⁺ than in D10 (*P < 0.005). b After 1 h incubation with MT the cells were washed to remove non internalized parasites, and maintained for 96 hs in medium with 1 % FBS. After fixation and Giemsa staining, the number of amastigotes per cell was counted. The values are the means ± SD of parasite numbers in 20 infected cells. The difference between strains 515 and CL was significant (*P < 0.005). Shown on the right is the image of a cell with amastigotes and trypomastigotes (arrows). Scale bar = 20 μm. c After 96 h of infection with the indicated parasite strains, HeLa cells were stained with Giemsa. Scale bar = 20 μm