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Updated: Jun 28, 2026
Collection and Processing of Lymph Nodes from Large Animals for RNA Analysis: Preparing for Lymph Node Transcriptomic Studies of Large Animal Species
Published on: May 19, 2018
Structure and function of rat lymph nodes
1Department of Anatomy, Faculty of Medicine and Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan. osmotani@med.u-toyama.ac.jp
Insights
Lymph nodes channel immune cells and antigens through specialized sinuses and parenchyma. High endothelial venules (HEVs) facilitate lymphocyte entry, with Aquaporin-1 suggesting water absorption.
Area of Science:
- Immunology
- Cell Biology
- Anatomy
Background:
- Lymph nodes are crucial sites for immune responses, integrating signals from lymph and blood.
- The lymph node structure includes endothelial-lined sinuses and a cellular parenchyma.
- Understanding lymph node architecture is key to deciphering immune cell trafficking and function.
Purpose of the Study:
- To elucidate the structural organization and fluid dynamics within lymph nodes.
- To identify key cellular components and their roles in immune cell navigation.
- To investigate the function of high endothelial venules (HEVs) in lymphocyte homing.
Main Methods:
- Microscopic examination of lymph node architecture.
- Analysis of lymphatic endothelial cell and reticular cell networks.
- Localization of specific markers like Aquaporin-1 and LYVE-1.
Main Results:
- Lymph nodes feature distinct sinuses (subcapsular, intermediate, medullary) and parenchyma (cortex, deep cortex, medullary cord).
- High endothelial venules (HEVs) express Aquaporin-1, indicating a role in water, but not protein, absorption from afferent lymph.
- Sinus reticular cells and macrophages form networks in medullary sinuses, guiding fluid and cell flow.
Conclusions:
- The lymph node's complex sinus system directs the flow of fluids and migrating cells.
- HEVs play a significant role in regulating fluid balance and lymphocyte entry into the node.
- The structural organization facilitates efficient immune surveillance and response initiation.
Abstract:
The lymph node comprises a critical crossroad for encounters between antigen presenting cells, antigens from lymph, and lymphocytes recruited into lymph nodes from the blood. The node consists of spaces lined with lymphatic endothelial cells and parenchyma. The former spaces can be divided into the subcapsular sinuses, lymphatic labyrinths in the deep cortex, intermediate sinuses, and medullary sinuses. The sponge-like framework of the node parenchyma is composed of collagen fibers invested with reticular cells. The parenchyma can be divided into the cortex, deep cortex, and medullary cord. Lymphocytes migrate from the node parenchyma into the lymphatic labyrinths in the deep cortex. Close to the labyrinths are high endothelial venules (HEVs), through which circulating lymphocytes enter the node parenchyma. HEVs strongly express Aquaporin-1, suggesting that HEVs are involved in the net absorption of water, but not protein, from lymph coming through afferent lymphatics. Many LYVE-1 positive sinus reticular cells (i.e., lymphatic endothelial cells) with attached macrophages form a network within the lumen of the medullary sinuses. Fluids and migrating cells arriving at the node preferentially flow through the subcapsular sinuses, intermediate sinuses, and medullary sinuses in this order. Fluids and migrating cells may also enter the cortex through gaps in the floor of the subcapsular sinuses.
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