At 24 and 32 hours post infection, we measured significantly lower levels of IL-1β, IL-6, MIP-3α, and KC/GRO in mice infected with the ΔlytS mutant as well as, for IL-2 cytokine, at 32 hours post infection (Fig. 5A through C, E and F). This evidence concerns the gene CXCL1 and infection.