Figure 4. Plasmodium-derived hypoxanthine induces TNF, PGE₂, and IL-6 release by DCs.

(A) DCs were incubated with P. yoelii-infected erythrocytes alone (black bars) or in the presence of allopurinol (white bars) for the indicated times. (B) DCs were pre-incubated with media alone (Control), uninfected erythrocytes (RBCs) or P. yoelii-infected erythrocytes (iRBCs) for 24 h in the presence or absence of allopurinol, before addition of LPS. Incubation media was collected after additional 24 h. (C) DCs were incubated with media alone (Control), the conditioned medium of uninfected erythrocytes (CM-RBC), or the conditioned medium of P. yoelii-infected erythrocytes (CM-iRBC) in the presence or absence of allopurinol for 24 h. (D) DCs were pre-incubated with media alone (Control), uninfected erythrocytes (RBCs) or P. yoelii-infected erythrocytes (iRBCs) for 24 h in the presence or absence of allopurinol. (E) DCs were incubated with P. yoelii-infected erythrocytes alone (black bars) or in the presence of allopurinol (white bars) for the indicated times. Incubation media were collected and TNF (A–C), PGE₂ (D) or IL-6 (E) concentrations were determined by ELISA. Data represent the average of triplicated samples with standard deviations. *P<0.05; **P<0.01.