Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease in infants. An imbalance of pro-inflammatory versus anti-inflammatory mediators is thought to play a key role which is mainly mediated by infection, mechanical ventilation and exposure to supplemental oxygen. In mammalian BPD models, several candidates targeting “sustained inflammation” were shown to decrease the severity of lung injury. The aim of this study is to determine whether anti-inflammatory agents prevent a pro-inflammatory response in monocyte-derived macrophages (MDM) of blood from preterm infants as an ex-vivo model of tissue-specific lung immunity. MDM will be challenged with toll-like receptor agonists and hyperoxia, mimicking a double-hit model of BPD. With our investigation we hope to contribute to new preventive strategies against sustained inflammation in the lung of preterm infants.