Furthermore, a protective role of GM-CSF in pneumococcal infection was described with intra-alveolar administration of this cytokine (Schmeck et al., 2004; Steinwede et al., 2011) and the resistance to lung infection attributed to the microbiota was found to be through GM-CSF signaling (Brown et al., 2017). This evidence concerns the gene CSF2 and pneumococcal infection.