Pertussis Toxin

T. gondii infection was established by intraperitoneal injection of ovalbumin-expressing Prugnauid strain (Pru^OVA) tachyzoites. Real time PCR was performed for chemokine receptor expression and T. gondii DNA quantification. Brain mononuclear cells were stained with fluorescently conjugated antibodies for flow cytometric analysis. OT-I cells were activated in vitro and transferred to recipient mice. Mice were treated with four doses of 100 μg of anti-CXCL10 for week-long depletion studies or 300 μg 18 hours prior to imaging studies. Pertussis toxin was administered at 400 μg/kg six hours before imaging. For MP microscopy, explant brain was imaged using a Leica SP5 2-photon microscopy system. Cell tracking was performed using Volocity software. In order to create displacement histograms without binning artifacts^{30 (link)} (Supplementary Tables 2-3), a constant number of displacements were placed in each bin. Various statistical methods were applied to test the validity of the generalized Lévy walk model (see Fig. 3, Supplementary Figs. 3, 5, 7, 8, 10, Supplementary Table 1, and Supplementary Discussion). Brownian dynamics-like simulations were performed to simulate the general behavior and searching capability of Gaussian (“random”) and Lévy walkers (see Supplementary Discussion). N searchers were placed in a spherical volume of radius b, and they moved stochastically until finding the target of radius a, which was stationary at the center of the sphere. During random walks, searchers moved 6DΔt = 0.1μm in the x-, y-, or z-direction each time step; here D is the motility coefficient and Δt is the time step. In Lévy walk simulations, a direction for a run was chosen at random, and run lengths were drawn from a Lévy distribution with exponent μ_run=2.15. Searchers moved a distance vΔt each time step until the run was completed. After each run, the walker paused for a time drawn from Lévy distribution with μ_pause=1.7.