Multimodal 4D imaging of cell-pathogen interactions in the lungs provides new insights into pulmonary infections

Lung efficiency as gas exchanger organ is based on the delicate balance of its associated mucosal immune system between inflammation and sterility. In this study, we developed a dynamic imaging protocol using confocal and twophoton excitation fluorescence (2PEF) on freshly harvested infected lungs. This modus operandi allowed the collection of important information about CX3CR1+ pulmonary cells. This major immune cell subset turned out to be distributed in an anisotropic way in the lungs: subpleural, parenchymal and bronchial CX3CR1+ cells have then been described. The way parenchymal CX3CR1+ cells react against LPS activation has been considered using Matlab software, demonstrating a dramatic increase of average cell speed. Then, interactions between Bacillus anthracis spores and CX3CR1+ dendritic cells have been investigated, providing not only evidences of CX3CR1+ cells involvement in pathogen uptake but also details about the capture mechanisms.