To evaluate the contribution of neutrophil-derived IL-1β in immunity against S. aureus skin infection, bone marrow-derived neutrophils isolated by Percoll density gradient centrifugation from wt or IL-1β-deficient donor mice were adoptively transferred into IL-1β-deficient recipient mice (wt PMN→IL-1β−/− mice or IL-1β−/− PMN→IL-1β−/− mice, respectively) (Fig. 4). This evidence concerns the gene IL1B and skin infection.