Adaptive Tumor Suppression
John Melford in Pocket Guide to Cancer, 2017
Among the components of the adaptive system are specialized white blood cells called lymphocytes of which there are two main types, B-cells and T-cells. These are created in the bone marrow by stem cells, and then circulate in the blood. T-cells migrate to the thymus where they reach maturity, hence the name T-cells. Mature B-cells and T-cells are deployed to lymph nodes and other lymphoid organs where they remain on alert to respond to a pathogen invasion. The lymphatic system consists of an extensive network of vessels that connect lymph nodes, the thymus, the spleen, adenoids, and tonsils. Lymph vessels are like arteries and veins that carry vital supplies of blood to all parts of the body. However, they are much finer and carry a colorless liquid called lymph. The primary function of the lymphatic system is to transport lymph, a fluid containing white blood cells, throughout the body. Unlike the blood system, which uses a pump to circulate fluid, movements of the body drive the circulation of the lymphatic system. This is a good reason to exercise regularly. There are hundreds of lymph nodes that serve as traps for pathogens, cancer cells and toxins to facilitate their removal. Thus, swollen lymph nodes may be indicative of an infection or a tumor. Those caused by infections come and go as we become ill and recover. Those caused by cancers are likely to persist.
Lymph Node
Joseph Kovi, Hung Dinh Duong in Frozen Section In Surgical Pathology: An Atlas, 2019
The lymph nodes are interposed along the course of the collecting lymphatic vessels. Lymph is carried to the nodes by the afferent lymphatic vessels which open into the subcapsular sinus. Lymph flows from the subcapsular sinus into the cortical and medullary sinuses, and leaves the node through the efferent lymphatic vessels at the hilus.42,100 The lymph node is structurally divided into three areas: the cortex, paracortex, and the medulla. Both the cortex and the medulla represent B cell (B lymphocyte) zones, whereas the paracortex contains only T cells. In the cortex are located the lymph follicles. The central pale area of the follicles is called the germinal (reaction) center. The germinal center contains different B cell variants: large and small cleaved cells, non-cleaved cells, immunoblasts, macrophages, and dendritic reticular cells. The germinal center is surrounded by a mantle of small lymphocytes, referred to as the corona. The follicles are the main site of humoral antibody production (Figure 78).42,99,101,102
The Lymphatic/Immune System and Its Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
The lymphatic system forms a secondary fluid circulation system that works in conjunction with the bloodstream to maintain the proper fluid levels of tissues. As a circulatory system, the lymphatics contain a complex series of vessels throughout the body similar to the veins of the bloodstream; they also contain a pumping mechanism to move the fluid known as lymph, although the "pump" consists of several structures and mechanisms rather than a single unit like the heart. The lymphatic system, however, also serves significant immune functions. The lymph nodes located along the lymphatic vessels filter the lymph, passing it over reticuloendothelial cells, which quickly remove bacteria and particulate matter from the lymph before it is returned to the bloodstream. Lymph nodes also produce the white blood cells known as lymphocytes, which attack and destroy bacteria and other invaders in the body.
Lymphatic targeting for therapeutic application using nanoparticulate systems
Published in Journal of Drug Targeting, 2022
Nidhi Singh, Mayank Handa, Vanshikha Singh, Prashant Kesharwani, Rahul Shukla
The lymphatic system was first recognised by Gasparo Aselli in the seventeenth century as per ancient text reports. It was later in the eighteenth century when various aspects of lymphatic system including its anatomy, got its attention and significance. Vascular system is further compartmentalised into lymphatic system that encompass different convoluted web of channels and hold a clear liquid termed lymph. Lymphatic system is composed of lymphatic duct, lymphatic capillaries, lymphatic vessel and some lymphatic organs including spleen and lymph node. Lymphatic vessels carry a clear watery fluid lymph, and white blood cells. Furthermore, lymphatic system is widely distributed in other parts of body in the form of lymph nodes, which is present in the neck, chest, armpit, groyne, abdomen. Lymphatic system maintains homeostasis and protection of the body tissues against different bacterial and viral infection by the mechanism of filtration. The lymphatic system not only filters the elements from lymph but avoid the first-pass hepatic metabolism of drugs directly via intestinal uptake [1]. This property plays an important role in tissue defense against infections by promoting the lymphocytic activity which in turn provides immunity or resistance. As mentioned, one of the major roles of the lymphatic system is to maintain water homeostasis in the body by recurring fluids present outside the body and oozing out into the blood circulation. It also enhances the absorption of antibiotics, water-insoluble vitamins, long-chain fatty acid and cholesterol ester.
Microspheres Encapsulating Immunotherapy Agents Target the Tumor-Draining Lymph Node in Pancreatic Ductal Adenocarcinoma
Published in Immunological Investigations, 2020
Booyeon J. Han, Joseph D. Murphy, Shuyang Qin, Jian Ye, Taylor P. Uccello, Jesse Garrett-Larsen, Brian A. Belt, Peter A. Prieto, Nejat K. Egilmez, Edith M. Lord, David C. Linehan, Bradley N. Mills, Scott A. Gerber
Lymphatics are conduits that allow both passive and active unidirectional transport of cells, molecules, and other particulates from tissue to lymph nodes (Swartz and Lund 2012). Here, we assessed whether MS could be visualized in TDLNs 2 h following intratumoral injection. While fluorescent MS were not observed in the non-draining pyloric lymph node (Figure 2a,b), abundant MS were distributed throughout the pancreatic TDLN, predominantly in the structural pattern of subcapsular and cortical sinuses (Figure 2c,d). The afferent lymphatic vessel, which was dissected with the TDLN, also contained numerous fluorescent MS (Figure 2e, gray arrows). Higher magnification demonstrated small, punctate fluorescent spheres co-localized along a vessel structure (Figure 2f). Collectively, these data suggest that MS injected locally into the pancreatic tumor traffic to the TDLN via lymphatics.
Engineering drug delivery systems to overcome mucosal barriers for immunotherapy and vaccination
Published in Tissue Barriers, 2020
Jacob C. McCright, Katharina Maisel
More recently, technologies have emerged that indirectly target lymph nodes by targeting lymphatic transport.120 The rationale behind targeting the lymphatic vessels is due to the transport functions of these vessels. Cells, fluids, protein, and small molecules are transported from peripheral tissues to the draining lymph nodes where adaptive immune responses are formed. Convective fluid flow in the interstitium drives fluid and molecules toward lymphatic vessels.120 This fluid flow becomes increasingly important with increased molecular size, as the opposing movement toward blood capillaries by diffusion decreases for larger molecules.120 At the same time, the extracellular matrix holding together the interstitium needs to be traversed, so particles need to be small enough to get across this extracellular matrix and reach lymphatic vessels and their downstream dLNs.
Related Knowledge Centers
- Extracellular Fluid
- Lymph Node
- Lymphatic Vessel
- Subclavian Vein
- Tissue
- Vein
- Venous Blood
- Lymphatic System
- Lymphocyte
- Lymph Capillary