In contrast to the control group of mice infected with P. yoelii 17XNL SPZ (Figure 7B, group 3) which developed parasitemia that steadily increased to reach a peak of around 20% at day 15 post-infection, mice that were previously immunized with IL-6 Tg-PbANKA/LISP2 SPZ and challenged with WT PbANKA SPZ showed only a limited parasitemia (1.8%) after a second challenge with P. yoelii 17XNL SPZ, which resolved rapidly and spontaneously until clearance by day 13 post-infection (Figure 7B, group 2). Here, IL6 is linked to infection.