The main goal of IMPORED is to study the interaction between two of the most important respiratory pathogens in humans, influenza virus and Streptococcus pneumoniae and to characterize the immune response in the host against a co-infection with both pathogens. Using molecular tools we will try to describe a model to predict when an infection with influenza virus will evolve to a dangerous pneumocal secondary infection.

Lay summary
Respiratory infections are one the leading causes of morbidity and mortality worldwide. Amongst the major respiratory pathogens, influenza virus and Streptococcus pneumoniae (the pneumococcus), have a health impact that is also responsible for billions in public money lost every year. Typically, scientific studies have focused on infections with single pathogens. However, it has been demonstrated that, in some cases, co-infection with a particular combination of pathogens results in a more severe clinical outcome compared with infection with either pathogen alone. Nevertheless, the mechanisms by which influenza infection may facilitate pneumococcal secondary infections remain unclear. This proposal regards the investigation of the host-pathogen interactions upon co-infection with influenza virus and S. pneumoniae, using state-of-the-art molecular techniques (microbiome analysis, microarray analysis) and intravital microscopy methods (2-photon microscopy) in the mouse model. We will use the well-studied association between influenza virus and Streptococcus pneumoniae infections to inform our investigation of their interaction with the other commensal bacterium and the host response. In the second aim we will examine in vivo the effects that the molecular mechanisms identified in the previous aim have in the establishment of a pneumococcal secondary infection.