Mice infected with 10,000 Pru-FLUC tachyzoites were imaged 7 days post-challenge using the in vivo imaging system (IVIS; Xenogen, Alameda, CA). Mice were injected i.p. with 200 μl of D-luciferin, anesthetized in an O 2 -rich induction chamber with 2% isoflurane, and imaged after 12 minutes. Photonic emissions were assessed using Living image® 2.20.1 software (Xenogen). Data are presented as pseudocolor representations of light intensity and mean photons/region of interest (ROI). All mouse experiments were repeated at least twice. There were 4-5 mice for each group. In the experiment in Figure 7b a subgroup of mice was used for studying immune response in parallel with the subgroup in the challenge shown.