Lymphatics immune system

One likely reason for the prevalence of helminths is their undoubted ability to down-regulate the host immune system at both the antigen-specific and polyclonal levels [3], In many chronic diseases, such as schistosomiasis and lymphatic filariasis, peripheral blood T cells show dramatically impaired parasite antigen-specific responsiveness [4], as discussed in more detail below. Moreover, from early reports of immunosuppression in animal models of infection, to studies in Africa linking vaccine failure to heavy helminth infection, there is clear evidence that infections can diminish reactivity to bystander antigens, particularly with increasing intensity of... 

Lymphocytes, mentioned in the description of the lymphatic system and its role in clearing paitieulates, have been the subject of much recent inquiry because of interest in the immune system (Golub, 1981). 

The common mucosal immune system (CMIS) is now well established as a separate component of the host s immune apparatus, quite distinct from and independent of the systemic immune system described above. Moreover, if an immune response is induced at one site in the mucosal system this generally leads to responses at distal mucosal sites of the CMIS, presenting a potentially large advantage. It should be noted that there are approximately 6 x 1010 antibody producing cells in mucosal tissues and 2.5 x 1010 lymphocytes in the entire lymphatic system. 

Diethylcarbamazine (Hetrazan) is used to treat certain roundworm infections of the lymphatics and connective tissues, including loiasis, onchocerciasis, and Bancroft filariasis. This agent immobilizes immature roundworms (microfilariae) and facilitates the destruction of these microfilariae by the body s immune system. Diethylcarbamazine is also effective against the adult forms of certain roundworms, but the mechanism of this anthelmintic action against mature nematodes is not known. 

Figure 6.15 Schematic diagram of a portion of the epithelium covering above a lymphatic nodule in a Peyer s patch (mouse). Attenuated M cells (M) extend as membranelike cytoplasmic bridges between the absorptive columnar epithelial cells present on either side (C). Beneath the M cell lies a small nest of intraepithelial lymphocytes (L) together with a central macrophage (Mac). The M cell provides a thin membrane-like barrier between the lumen above and the lymphocytes in the intercellular space below. This M cell has taken up the macromolecules and particulate matter that reach it and macrophages (Mac) may ingest them. Modified from D.H. Cormack. Lymphatic tissue and the immune system. D.H.Cormack (ed.) (1987) Ham s Histology, J.B. Lippincott Company, Philadelphia, pp. 234-263...

Figure 6.16 The common mucosal immune system (CMIS). Uptake of antigen by the M cells of the Peyer s patches stimulates the production of Ig-A committed B cells and T helper cells. These cells migrate through the lymphatics and...

Immune system Hematology/clinical chemistry Organ weights Histopathology Antibodies Imm unoglobulins Immunophenotyping NK cell activity" Lymphocyte proliferation TDAR and DTH CD immunohistochemistry of lymphatic organs Cytokines... 

During initial contact with the drug, the immune system is sensitized antigen-specific lymphocytes of the T-type and B-type (antibody formation) proliferate in lymphatic tissue and some of them remain as so-called memory cells. Usually, these processes remain clinically silent. 

The activation of the stress systems affects all tissues of the organism, and the peripheral immune system is no exception. These effects are mediated through at least tw o pathways via the HPA axis and by virtue of the innervation of lymphatic tissues by autonomic nerve fibers, especially from the sympathetic nervous system. All lymphoid tissues, primary (bone marrow and thymus) as well as secondary (spleen, lymph nodes, and gut-associated lymphoid tissue) are innervated by sympathetic nerve fibers. As discussed above, most lymphoid cells express catecholamine receptors, including B-lymphocytes, CD4- and CD 8-positive T cells, dendritic cells, monocytes, and macrophages. 

Lymphocyte—cell that functions as part of the lymphatic and immune systems by attacking specific invading substances. 

The lymphatic system, also known as the immune system, defends the body against microorganisms and other foreign bodies. Additionally, the lymphatic system transports fluids from the body s tissues to the blood, thus helping to control fluid balance in the body. This system also absorbs substances from the digestive system. The organs of the lymphatic system include the lymph, lymph nodes, lymph vessels, thymus, spleen, and tonsils. 

When invading microorganisms have crossed the epithelial barriers they will almost certainly be taken up with lymph in the lymphatic ducts and be delivered to filtration and immune systems at the local lymph nodes. Sometimes this serves to spread infections further around the body. Eventually, spread may occur from local to regional lymph nodes and thence to the bloodstream. Direct entry to the bloodstream from the primary portal of entry is rare and will only occur when the organism damages the blood vessels or if it is injected directly into... 

Tuberculosis (TB) is a lower respiratory infection caused by bacillus Mycobacterium tuberculosis, which is commonly called tubercle bacillus and is an acid-fast bacillus (AFB). Tuberculosis is transmitted by droplets dispersed in the air through coughing and sneezing and inhaled into the alveoli of the lung. Tuberculosis spreads from the lungs to other organs via the blood and lymphatic system in patients with a compromised immune system. 

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