Neutrophil Identification Workflow

BAL cells were stained with the Live/Dead Fixable Near-IR-Dead Cell staining kit (Invitrogen) for 20 minutes in PBS prior to blockade with anti-CD16/CD32 Fc receptor block (BD Pharminogen) for 20 minutes. Cells were then washed in PBS containing 0.1% sodium azide and 1% BSA followed by staining for surface markers at 4⁰C for 30 minutes. Details of antibodies used are shown in Supplementary Table 1. Cells were subsequently washed in PBS containing 0.1% sodium azide and 1% BSA before fixation in 2% paraformaldehyde. Neutrophils were identified using the following surface markers, as previously described^{60 (link)}: The gating strategy adopted is shown in Supplementary Fig. 5.