Coupe d'intestin grêle de souris observée en microscopie confocale multi-couleur
Cross-section of the small intestine of a mouse, observed using multicolour confocal microscopy. Immunofluorescent marking reveals epithelial cells (EpCAM) in cyan, paneth cells in grey, T lymphocytes (CD3) in orange, phagocytes (CD11c) in red, leukocytes (CD45) in dark blue, M lysozyme (via GFP expression) in green, and collagen in yellow. The image was obtained by combining several lasers and a spectral detector able to distinguish a wide range of fluorochromes, i.e. colours. A 20X oil-immersion objective lens was used. With confocal microscopy, laser beams scan the specimen at high speed, point by point. This technique can be used to produce thin optical cross-sections (at various specimen thicknesses) that reveal the locations of numerous structures and cell types (T and B lymphocytes, dendritic cells, macrophages, actin filaments, nuclei, etc.) in a tissue slice. These optical cross-sections are then stacked to generate 3D images of the specimens. This enables scientists to compare the locations and numbers of entities in various circumstances, such as in patients suffering from diseases, for example, in order to shed light on the workings of the immune system. This technique is constantly being improved in terms of its resolution and sensitivity, as well as the possible colours and contrasts.