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An Introduction to the Immune System and Vaccines
Published in Patricia G. Melloy, Viruses and Society, 2023
The cells, tissues, organs, and vessels of the immune system of the human body are physically known as the lymphatic system. Lymphatic tissue can also be found in other body systems, including the digestive system and the respiratory system. Lymph, a fluid that circulates in the body independent of blood, flows into lymph nodes (glands) that are connected by lymphatic vessels. Organs such as the spleen, thymus, and bone marrow are all networked with the lymph nodes through the lymphatic system (Ross and Pawlina 2011). Lymph nodes can filter lymph and are major sites where immune reactions take place (Cruse and Lewis 2009). The major parts of the lymphatic system are shown in Figure 2.2.
The immune and lymphatic systems, infection and sepsis
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Michelle Treacy, Caroline Smales, Helen Dutton
Lymphoid tissue is composed of reticular connective tissue, which provides support for lymphocytes and macrophages. These lymphocytes and macrophages can quickly squeeze through the capillary walls to circulate in the blood. This recirculation of lymphocytes between the blood, lymphatic tissues and organs is vitally important in exposing many lymphocytes to an invading pathogen or antigen. Depending on the route of entry the antigen, will be conveyed from the site of infection to the lymphatic tissues, where antigen-presenting cells, e.g., dendritic cells of lymphoid tissue and macrophages, are waiting to phagocytose the microbes and present the microbial antigen on their surface for antibodies to respond to. Antigens causing a tissue infection will be conveyed to the appropriate draining lymph nodes: the lymph node effectively closes down to retain the antigen-specific cells within the lymph node, thereby containing the infection within a small area (Stewart 2012). This causes swollen, painful lymph nodes, as experienced with an infection within the tonsils (tonsillitis). Cancerous cells can also be trapped within the lymph node: the node may become swollen but not painful, which is a useful sign in differentiating between infection and cancer.
The Hematologic System and its Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
Along with red blood cells, the bone marrow also produces white blood cells (WBCs), also called leukocytes (leuko- = white) because they lack hemoglobin and its red color. Some leukocytes, however, are formed in the lymphatic system rather than bone marrow. Leukocytes differ from erythrocytes in two major ways—they have a nucleus, and they serve mainly to defend the body from invading organisms and other substances. Leukocytes can be divided into three main types: granulocytes, monocytes, and lymphocytes. Granulocytes evolve from myeloblasts (myelo- = marrow) in the bone marrow, while lymphocytes and monocytes are formed in lymphatic tissue.
Advances, challenge and prospects in cell-mediated nanodrug delivery for cancer therapy: a review
Published in Journal of Drug Targeting, 2023
Wuhao Wei, Yuansheng Zhang, Zhizhe Lin, Xin Wu, Wei Fan, Jianming Chen
T cells exist in almost all organs and tissues of the body, predominantly in lymphatic tissues. They mainly differentiate into CD4+ helper T cells and CD8+ cytotoxic T cells to assume the responsibility of establishing and maintaining an immune response, homeostasis and memory [72]. T cells themselves hold a non-specific destroying effect on tumour cells. CAR-T cells (chimeric antigen receptor T cells) have been artificially implanted with specific tumour antigen recognition receptors, targeting tumour cells and producing cytotoxic effects [73]. Gardner and his team proposed a bold vision for CAR-T cells by transforming CAR-T cells into ‘micropharmacies’ for anticancer drugs, which may denote a good application prospect of T cell-loaded NPs [74]. This approach has been explored by Siriwon et al.’s research, which indicated that crosslinked multilamellar liposomal vesicles (cMLV)- loaded with A2aR-specific small molecule antagonists can covalently attach to CAR T cell surface via maleimide. It is noteworthy that this hitchhiking approach does not affect the activity and function of CAR T cells. Meanwhile, thanks to the homing properties of CAR T cells, a2AR-containing nanoparticles can be effectively localised in tumour tissues, thus rescuing functionally deficient tumour-resident T cells. CAR T cell-mediated nanomedicine delivery has shown great potential in tumour prevention and therapeutic efficacy evaluation [75].
Apyrase decreases phage induction and Shiga toxin release from E. coli O157:H7 and has a protective effect during infection
Published in Gut Microbes, 2022
Ida Arvidsson, Ashmita Tontanahal, Karl Johansson, Ann-Charlotte Kristoffersson, Sára Kellnerová, Michael Berger, Ulrich Dobrindt, Diana Karpman
The number of apoptotic cells in intestinal sections from mice sacrificed on day 2 was assessed by the TUNEL assay. Apoptotic cells were observed on the luminal side of the intestine, Figure 6. Staining was also observed in lymphatic tissue both in infected and uninfected mice. The number of dying cells was quantified and is presented as the number of TUNEL-positive cells/100 000 μm2. The highest number of apoptotic cells was observed in the group infected with E. coli O157:H7 and left untreated, Figure 6a. Few TUNEL-positive cells were found in mice infected with E. coli O157:H7 and treated with apyrase (Figure 6b) and in uninfected controls that were untreated (Figure 6c) or treated with apyrase, Figure 6d. A higher number of apoptotic cells was observed in the intestines of the mice infected with E. coli O157:H7 and left untreated (median 27.6, range 10–70.6 cells/100 000 μm2) compared to mice infected and treated with apyrase (median 5.2, range 3–8.2 cells/100 000 μm2) P < 0.05, Figure 6e. The uninfected controls showed minimal TUNEL-positive cells (vehicle, median 1.1, range 0–5 cells/100 000 μm2 and apyrase-treated, median 3.6, range 1–14.8 cells/100 000 μm2).
The Expression of Matrix Metalloproteinases in Eyes with Intraocular Lymphoma
Published in Ocular Immunology and Inflammation, 2022
Kanae Fukutsu, Satoru Kase, Daiju Iwata, Kayo Suzuki, Kenichi Namba, Susumu Ishida
Malignant lymphoma is a general term for malignant tumors with monoclonal proliferation of lymphoid cells. It is classified into two categories: Hodgkin lymphoma that disturbs lymphatic tissues systemically, and the other is non-Hodgkin lymphoma. Most of the intraocular lymphoma (IOL) cases are Non-Hodgkin lymphoma, in which diffuse large B-cell lymphoma (DLBCL) is the most common histopathological type.1 IOL is often classified into two categories: the primary IOL (PIOL) which means IOL possibly arising from the vitreoretinal tissues, as well as the intraocular involvements from primary central nervous system lymphoma (PCNSL). The secondary IOL (SIOL) is a metastasis of lymphoma outside the central nervous system. PIOL often masquerades as infectious/noninfectious uveitis, while SIOL usually invades the choroid and manifests as thickened choroid. When patients are suspected of IOL, surgically obtained cell-block from vitreous samples is suggested as an advantageous tool to make an accurate diagnosis.2–4