Prepubertal vs pubertal lung gene expression during influenza in female mice

During the 1918 influenza pandemic, children experienced substantially lower mortality than adults, a striking but poorly understood finding. Whether this was due to enhanced resistance (reduced virus load) or better tolerance (reduced impact of infection) has not been defined. We found that prepubertal mice infected with H1N1 influenza virus also showed greater survival than infected pubertal mice, despite similar virus loads. To explore mechanisms for the survival differences, we compared gene expression profiles in lung tissue from mice of both age groups during the course of influenza pneumonia. Female C57Bl/6 mice were infected with PR8 H1N1 influenza (87.5 PFU) at age 25 days (pre-pubertal) or age 28 days (pubertal) and lung tissue was collected on days 3, 6, and 9 after infection, as well as from vehicle-treated control mice for each age group, with 3-4 mice/group.