Lymph node cortical sinus organization and relationship to lymphocyte egress dynamics and antigen exposure

The Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, CA 94143, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 11/2010; 107(47):20447-52. DOI: 10.1073/pnas.1009968107
Source: PubMed


Recent studies have identified cortical sinuses as sites of sphingosine-1-phosphate receptor-1 (S1P(1))-dependent T- and B-cell egress from the lymph node (LN) parenchyma. However, the distribution of cortical sinuses in the entire LN and the extent of lymph flow within them has been unclear. Using 3D reconstruction and intravital two-photon microscopy we describe the branched organization of the cortical sinus network within the inguinal LN and show that lymphocyte flow begins within blunt-ended sinuses. Many cortical sinuses are situated adjacent to high endothelial venules, and some lymphocytes access these sinuses within minutes of entering a LN. However, upon entry to inflamed LNs, lymphocytes rapidly up-regulate CD69 and are prevented from accessing cortical sinuses. Using the LN reconstruction data and knowledge of lymphocyte migration and cortical sinus entry dynamics, we developed a mathematical model of T-cell egress from LNs. The model suggests that random walk encounters with lymphatic sinuses are the major factor contributing to LN transit times. A slight discrepancy between predictions of the model and the measured transit times may be explained by lymphocytes undergoing a few rounds of migration between the parenchyma and sinuses before departing from the LN. Because large soluble antigens gain rapid access to cortical sinuses, such parenchyma-sinus shuttling may facilitate antibody responses.

Download full-text


Available from: Irina L. Grigorova
    • "The fluid flow through the node has been linked to reducing the preference of cells to migrate within the node, causing more of the immune cells to exit the node (Grigorova et al. 2010). As the lymph nodes are involved in antigen sensing and immune cell activation, understanding how fluid is transported through the node could be useful for developing knowledge of how fluid movement affects the immune response of the node. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The lymphatic system returns fluid to the bloodstream from the tissues to maintain tissue fluid homeostasis. Lymph nodes distributed throughout the system filter the lymphatic fluid. The afferent and efferent lymph flow conditions of lymph nodes can be measured in experiments; however, it is difficult to measure the flow within the nodes. In this paper, we present an image-based modelling approach to investigating how the internal structure of the node affects the fluid flow pathways within the node. Selective plane illumination microscopy images of murine lymph nodes are used to identify the geometry and structure of the tissue within the node and to determine the permeability of the lymph node interstitium to lymphatic fluid. Experimental data are used to determine boundary conditions and optimise the parameters for the model. The numerical simulations conducted within the model are implemented in COMSOL Multiphysics, a commercial finite element analysis software. The parameter fitting resulted in the estimate that the average permeability for lymph node tissue is of the order of magnitude of [Formula: see text]. Our modelling shows that the flow predominantly takes a direct path between the afferent and efferent lymphatics and that fluid is both filtered and absorbed across the blood vessel boundaries. The amount that is absorbed or extravasated in the model is dependent on the efferent lymphatic lumen fluid pressure.
    No preview · Article · Dec 2015 · Bulletin of Mathematical Biology
  • Source
    • "Images were processed and analyzed using Volocity imaging software. Histocytometric analysis of reconstructions was performed with CellProfiler (Carpenter et al., 2006; Grigorova et al., 2010), and CellProfiler Analyst (Hickman et al., 2008; Jones et al., 2008; León et al., 2012). Analysis of reconstructions was performed with individual XY imaging planes, which were representative of at least 400 µm of reconstructed LNs. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Dendritic cells (DCs) are well established as potent antigen-presenting cells critical to adaptive immunity. In vaccination approaches, appropriately stimulating lymph node-resident DCs (LNDCs) is highly relevant to effective immunization. Although LNDCs have been implicated in immune response, their ability to directly drive effective immunity to lymph-borne antigen remains unclear. Using an inactive influenza vaccine model and whole node imaging approaches, we observed surprising responsiveness of LNDC populations to vaccine arrival resulting in a transnodal repositioning into specific antigen collection sites within minutes after immunization. Once there, LNDCs acquired viral antigen and initiated activation of viral specific CD4(+) T cells, resulting in germinal center formation and B cell memory in the absence of skin migratory DCs. Together, these results demonstrate an unexpected stimulatory role for LNDCs where they are capable of rapidly locating viral antigen, driving early activation of T cell populations, and independently establishing functional immune response.
    Full-text · Article · Jul 2014 · Journal of Experimental Medicine
  • Source
    • "In contrast to PROX1, expression of LYVE1, one of the most widely used markers of LECs in normal and tumor tissues, was restricted to the paracortical and medullary sinuses in most LNs, and was not expressed by PROX1+ LECs in the subcapsular and trabecular sinuses. This distribution pattern differs from that observed in murine LNs, where LYVE1 is expressed by sinuses throughout the LN [2], [17]. Previous studies assessing LYVE1 in human LNs did not report the disparity of expression between sinuses in different regions, perhaps due to their focus on medullary sinuses [9], [14]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The lymphatic sinuses in human lymph nodes (LNs) are crucial to LN function yet their structure remains poorly defined. Much of our current knowledge of lymphatic sinuses derives from rodent models, however human LNs differ substantially in their sinus structure, most notably due to the presence of trabeculae and trabecular lymphatic sinuses that rodent LNs lack. Lymphatic sinuses are bounded and traversed by lymphatic endothelial cells (LECs). A better understanding of LECs in human LNs is likely to improve our understanding of the regulation of cell trafficking within LNs, now an important therapeutic target, as well as disease processes that involve lymphatic sinuses. We therefore sought to map all the LECs within human LNs using multicolor immunofluorescence microscopy to visualize the distribution of a range of putative markers. PROX1 was the only marker that uniquely identified the LECs lining and traversing all the sinuses in human LNs. In contrast, LYVE1 and STAB2 were only expressed by LECs in the paracortical and medullary sinuses in the vast majority of LNs studied, whilst the subcapsular and trabecular sinuses lacked these molecules. These data highlight the existence of at least two distinctive populations of LECs within human LNs. Of the other LEC markers, we confirmed VEGFR3 was not specific for LECs, and CD144 and CD31 stained both LECs and blood vascular endothelial cells (BECs); in contrast, CD59 and CD105 stained BECs but not LECs. We also showed that antigen-presenting cells (APCs) in the sinuses could be clearly distinguished from LECs by their expression of CD169, and their lack of expression of PROX1 and STAB2, or endothelial markers such as CD144. However, both LECs and sinus APCs were stained with DCN46, an antibody commonly used to detect CD209.
    Full-text · Article · Apr 2014 · PLoS ONE
Show more