Fig. 5: Pulmonary leptin administration reduces airway immune responses to influenza infection in mice.

a BALB/c mice were treated with intranasal leptin protein (16μg) or vehicle control, 12 h prior to infection with Influenza X31 or PBS control. b Ifnβ, 2’-5’Oas, Viperin and PKR lung mRNA expression measured by qPCR at 6 h post-infection. c BAL neutrophils and activated neutrophil subsets (CD63+ and CD64+) enumerated by flow cytometry at 72 h post-infection. BAL concentrations of (d) IL-1β, (e) IL-6 and (f) TNF measured by ELISA at 72 h post-infection. g Lung Socs3 mRNA expression at 18 h following leptin administration. h BAL macrophages were harvested from naïve untreated mice and cultured ex vivo followed by treatment with leptin protein (32 and 320 µg/ml) for 12 h before infection with Influenza X31. i Ifnβ, 2′−5′Oas, and PKR mRNA expression in cell lysates at 6 h post-infection. j Socs3 mRNA expression at 18 h following leptin administration. Data are presented as mean (±SEM) for n = 5 mice per group in b–g and n = 5 for i, j. Statistical significance analysed using one-way ANOVA with Bonferroni post-test. *P < 0.05, **P < 0.01, ***P < 0.001. Source data are provided as a Source Data file.