Suggesting low systemic response, the blood of mice trained 9 weeks contained lower levels of a broad range of cytokines (IL-1β, IL-6, IL-10, IL-12p40, IL-17A, IL-18, IFNγ, TNF, CCL2 and CXCL5) 2 days after infection with L. monocytogenes (Figure 8A). Here, CCL2 is linked to infection.