Three-dimensional reconstructions of murine lymph nodes by means of high resolution X-ray phase-contrast tomography reveal the functional composition of vascular networks and general lymph node structure

by Schütz Paul (INI Research)

Tuesday 1 Mar 2022, 13:15 → 14:00 Europe/Berlin

Online

With growing molecular evidence for correlations between spatial arrangement of blood vasculature and fundamental immunological functions, carried out in distinct compartments of the subdivided lymph node, there is an urgent need for three-dimensional models that can unite these aspects. We reconstructed such models at a 1.84 µm resolution by the means of speckle-based X-ray imaging with a 2D grating in a short time without any staining. While conventional illustrations of mammalian lymph nodes depict the hilus as a definite point of blood and lymphatic vessel entry and exit, our method revealed that multiple branches enter and emerge from an area that extends up to one third of the organ’s surface. This could be a prerequisite for the drastic and location-dependent remodeling of vascularization, which is necessary for lymph node expansion during inflammation. Contrary to corrosion cast studies we identified B-cell follicles exhibiting a two times denser capillary network than the deep cortical units of the T-cell zone. In addition to our observation of high endothelial venules spatially surrounding the follicles, this suggests a direct connection between morphology and B-cell homing. Our findings will deepen the understanding of functional lymph node composition and lymphocyte migration on a fundamental basis.