Figure 4.

In vitro kinetics of Leishmania intracellular growth after 3T3-Ad infection, and parasite viability. The mean number of amastigotes per 3T3-Ad ± standard deviation was determined after infection with promastigotes (A) or axenic amastigotes (B) and incubation for 1, 24, 48 and 144 h, for L. (L.) amazonensis and L. (V.) braziliensis. At least 100 3T3-Ad cells were counted per condition. Assays were performed in triplicate and the assays were repeated at least twice. Asterisks indicate a statistically significant difference (p-value < 0.05) for each time point vs. 1 h (Student’s t test). Numbers in the bars indicate the mean of infected 3T3-Ad (%) per condition. (C, D): Growth curves of parasites recovered from 3T3-Ad infections with promastigotes or amastigotes, respectively, after 144 h. Amastigote-promastigote differentiation was carried out as described in the ‘Methods Section’ and recovered parasites resuspended in M199 were kept at 25°C. On the 3rd day, promastigotes were observed, which grew exponentially until reaching the maximum density peaks around day 7. Experiments represent the mean of triplicates ± standard deviation.