FIG. 4.

TNF-α expression by E. histolytica DNA-stimulated macrophages requires endosomal acidification. RAW 264.7 macrophages were pretreated for 30 min with or without chloroquine (5 μg/ml) or monensin (20 μM) and subsequently stimulated for 3 h with E. histolytica (E.h) DNA (30 μg/ml), S. enterica serovar Typhimurium (S.t) DNA (30 μg/ml), or LPS (1 μg/ml). mRNA was collected, and the level of TNF-α expression was measured by real-time PCR. Data points represent means ± standard errors of the means of the results obtained from three experiments. An asterisk indicates a significant decrease in level compared to the results obtained with cells not treated with inhibitors (P < 0.05).