Development of lung fibrosis with prolonged exposure of mice to P. agglomerans antigen was associated with progressive intensification of deposition of the extracellular matrix components; increased concentrations of TGFβ and FGF2; disorders of respiratory function, including the increase of frequency of breathing (F) and a decrease of inspiratory and expiratory times (Ti and Te) in both investigated time points, as well as an increase of MV (minute volume) and EF50 (mid-tidal expiratory flow) on day 28 of inhalations. Here, FGF2 is linked to pulmonary fibrosis.