FIG. 4.

Parasite survival in macrophages from TLR4^0/0 and wild-type mice. BMMφ (5 × 10⁵ ml⁻¹) from naïve wild-type (black bars) and TLR4^0/0 (open bars) mice were infected with 25 × 10⁵ L. major parasites ml⁻¹ in the presence of IFN-γ (20 U ml⁻¹) and TNF-α (200 U ml⁻¹) (Th1 conditions) or IL-4 (20 U ml⁻¹) (Th2 conditions). After 48 h of incubation, macrophages were lysed and a limiting dilution assay was performed to determine the number of viable parasites. Data show the results of one representative experiment of four independent experiments. In addition, gene expression was analyzed by semiquantitative RT-PCR. Samples were standardized by densitometric comparison with the amplification of the housekeeping gene β-actin. Data show the results of one representative experiment of two independent experiments.