FIG 5.
IL-12 but not IL-10 contributes to STAg-induced protection. Approximately 8-week-old C57BL/6 wt or IL-10−/− (A and B) or 6-week-old wt or IL-12βR−/− (C and D) mice were inoculated with 1 × 106 iRBCs and treated with PBS or STAg 24 h later. (E and F) wt C57BL/6 mice were inoculated with 1 × 106 iRBCs and treated with increasing amounts of recombinant purified IL-12p70 at 24 h postinfection. Symptoms of ECM were monitored, and mice with scores ≤ 5 were euthanized (A, C, and E). Thin blood smears were prepared 6 days after P. berghei ANKA infection, and the percentage of iRBC was determined after treatment with Giemsa stain (B, D, and F). Survival significance was determined by Mantel-Cox log rank analysis comparing PBS or P. berghei alone to coinfection or STAg treatments. iRBC significance was determined by a Kruskal-Wallis test. *, P < 0.05; **, P < 0.01; ***, P < 0.001. Two independent experiments are shown in panels A to C, and a representative experiment is shown for panels D to F.