IL6 and infection: Therefore, the comparison between mice strains shows that BALB/c mice have higher values of the proinflammatory cytokines (IFN-γ and IL-6) and the anti-inflammatory cytokines (IL-10 and IL-4) in response to infection than C57BL/6 mice (Welch two-sample t test, P < 0.05) (see Fig. S1 in the supplemental material).