Figure 5

Downregulation of proinflammatory cytokine mRNA is closely associated with higher level of parasite load in TLR2^−/− mice.

WT, TLR4^−/− and TLR2^−/− mice (n = 5) were left uninfected or challenged with sporozoites by i.v. (A), 42 h later, the mRNA levels of the indicated proinflammatory cytokines were determined with SYBR semi-quantitative RT-PCR. All data were presented as the ratio of the proinflammatory cytokines to the GAPDH control. (B), WT and TLR2^−/− mice (n = 5) were challenged with or without sporozoites by mosquito bite and the proinflammatory cytokine mRNAs were determined as above. (C), TLR2^−/− mice (n = 5) challenged i.v. with sporozoites were left untreated or co-treated with IL-6, TNF-α or IFN-γ. 42 h later, the liver parasite burden was determined by real time PCR as described previously. All the experiments were repeated for three times and all data were presented as the mean ± SD, *p < 0.05; **p < 0.01.