Poster Presentation Australasian Society for Immunology Annual Scientific Meeting 2014

Understanding lymph node vasculature on a global scale – Combined 3D imaging and computational analysis of blood and lymphatic networks across entire lymph nodes (#226)

Inken Kelch 1 2 , Gib Bogle 1 3 , Anthony Phillips 1 2 4 , Greg B. Sands 3 , Ian J. LeGrice 3 5 , Dane A. Gerneke 3 , Claudia J. Mansell 1 2 , Rod Dunbar 1 2
  1. Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
  2. School of Biological Sciences, The University of Auckland, Auckland, New Zealand
  3. Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
  4. Department of Surgery, The University of Auckland, Auckland, New Zealand
  5. Department of Physiology, The University of Auckland, Auckland, New Zealand
Adaptive immunity against pathogen challenge is organised within lymph nodes (LNs), small organs that enable constant screening of tissue-derived material by circulating lymphocytes in designated compartments and facilitate the establishment of immune responses. A central feature of their specialised microanatomy is an intricate network of blood and lymphatic channels, which serve as entry and exit routes for immune cells and lymph, thereby orchestrating the course of immune cell migration and antigen transmission. However, we currently lack understanding of the global organisation of both vascular systems and their structural dynamism during inflammation, when LNs increase rapidly in size in response to changes in cell trafficking. To gain better insight into the spatial organisation of blood and lymphatic systems, we aimed to generate high-resolution images of entire LNs and describe the vascular topology with the help of sophisticated computer analysis and visualisation tools. Using a unique automated confocal imaging system we generated unprecedented 3D images of blood and lymphatic channels in murine LNs at subcellular resolution, which provided new insights into their labyrinthine arrangement and regional specialisation. Moreover, we developed custom image-processing and analysis tools to assess the vascular volumes and distances between blood and lymphatic channels. Detailed quantification of the blood vessel network yielded information about vessel diameters, lengths, and densities in 2D and 3D. In addition, we established methods to compare vessel parameters in LN subregions such as the T and B cell zones and evaluated the distribution of HEVs. In a first attempt to quantify changes in reactive LNs we analysed the vascular systems of an LPS-stimulated LN and found the blood vasculature significantly expanded after just two days compared to unstimulated controls. These methods can now be used to further investigate vascular remodelling processes during LN activation, and will help us to map LN anatomy more comprehensively.