IL-17A depletion significantly inhibited neutrophil recruitment into the airways, decreased airway inflammation and AHR, with no significant effect on eosinophil recruitment or IL-5 and IL-13 production, suggesting that IL-17A-mediated neutrophilic inflammation plays an important role in the promotion of asthma development in adulthood by neonatal S. pneumoniae lung infection. The gene discussed is IL17A; the disease is asthma.