Fig.1 Neutrophil depletion at the end of the first week p.i. (postinfection) enhances survival in aged mice. a Young mouse were administered a neutrophil-depleting monoclonal antibody just prior to inoculation with influenza virus and following infection (as described in Materials and methods) and survival was monitored. Compared to isotype control treated mice, neutrophil-depleted young mice exhibited a significant increase in mortality. *P < 0.05 (Log rank), n = 8–10 per group. b Aged mice were treated per a and survival postinfection was monitored. P value between neutrophil-depleted and control group, P=0.23 (Log-Rank). n=8–10 per group. c Young mice were administered a neutrophil-depleting antibody at day +6 p.i., then intermittently until day +12 p.i. (as described in Materials and methods) and compared to isotype control treated, young infected mice. *P = 0.10 (Log-rank), n = 8–10 per group. d Aged mice were treated according to c and survival was measured postinfection. Aged neutrophil-depleted mice exhibited a significant increased survival as compared to the control group. *P < 0.05 Log-rank, n = 8–10 per group