Figure 2.

Analysis of failed IV challenge experiments. Failed (i.e., less than 90% of naïve mice challenged with 300 SPZ became infected) challenge experiments showed one of two titration patterns. Type 1 challenge failures (dotted line) showed a direct relationship between sporozoites dose and percent of mice infected. Type 2 failures (solid line) showed an inverse relationship between sporozoites dose and the percentage of mice infected. N = 10 mice/group for each experiment. Shown are the average numbers of infected animals from independent challenge experiments ± SEM.