CCL2 and infection: Interestingly, H7N7 infection did not significantly increase the above chemokines and cytokines in the brains of previously vaccinated mice compared with vaccinated mice receiving PBS (CCL2: p = 0.44, IFNγ: p = 0.87, IL1β: p = 0.68, IL-6: p = 0.18, TNFα: p = 0.14).