Transcripts encoding cytokines and chemokines such as IL-1β (interleukin-1β), IL-18, IL-6, IFN-γ, IL-10, CCL2 (C-C motif chemokine ligand 2), CCL4 and CCL7 were also up-regulated in the lungs during infection (Figure S1b). Here, CCL2 is linked to infection.