Lymphoid tissues

Generation of such memory cells is the goal of vaccination against viral and bacterial infections. Today, the best way to achieve this goal is vaccination using attenuated hve pathogens. 

Different types of regulatory cells also actively contribute to the programming and maintenance of peripheral tolerance by production of IL-10 and TGF-p family cytokines. 

Regulation of Immune Cells Activity by Neurotransmitters and Neuropeptides 

Macrophages/DCs and lymphocytes express a variety of adrenergic receptors. Increased concentrations of NE or dopamine can modulate T cells polarization toward Th2 profile, stimulate IL-4, IL-5, and IL-13 secretion (Kohm and Sanders, 2001). The same Th2 polarization can be induced by histamine, serotonin, neuropeptides such as substance P, vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating polypeptide, calcitonin gene-related peptide, a-melanocyte-stimulating hormone, and leptin (Steinman, 2004). 

Briefly summarize the major steps in lymphocyte embryonic development. 

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One component of the age-ielated decline in immune function is decreased production of the lymphokine that promotes the growth of T-ceUs, interleukin 2 (IL-2). Administration of recombinant-derived IL-2, both in vitro and in vivo, appears to restore certain immune functions in aged mice. Recovery of T-regulatory effects on B-ceU differentiation has been reported in human cells from elderly patients treated with IL-1 and/or IL-2 (42). Similar effects have been observed in the presence of the pentapeptide thymopentin [69558-55-0] (Arg Lys Asp Val Tyr), a weU-known IL-2 inducer. Recombinant IL-2 adrninistered to aged mice for three weeks has been shown to correct the T-ceU functional deficiency associated with antigen-specific immunoglobulin production by certain lymphoid tissue (43). 

British investigators (Haddow and Timmis 1951) synthesized and studied esters of the methanesulfonic acid. The most active derivative was the dimethylsulfonic ester of 1,4-butanedione, known as busulfan. Busulfan interacts with the thiol groups of proteins and amino acids some of its metabolites can alkylate the thiols of cysteine, peptides and proteins. Busulfan exerts selective cytotoxic activity in hematopoietic bone marrow cells and inhibits the formation of granulocytes and platelets. It slightly affects the lymphoid tissue. 

Dendritic cells (DC) are important antigen-presenting cells mostly derived from the bone marrow. Microscopically they show characteristic long cytoplasmic extensions called dendrites. There are several types of specialized DC present in all lymphoid tissues and major... 

In the specialized environment of secondary lymphoid tissues such as lymph nodes or spleen, dendritic cells provide the requirements for naive T-lymphocytes to become activated and to proliferate. The professional antigen-presenting cells present peptides in MHC II, express costimulatory molecules, and release cytokines into the immunological synapse, which is formed by the antigen-presenting cell and the naive T-lymphocyte. Thus, cells of innate immunity initiate and facilitate the activation of naive lymphocytes, and it is easily conceivable that their cytokines and adhesion molecules will instruct the naive T-lymphocyte during activation and differentiation to T-effector cells. 

This experimental drug is a derivative of myriocin. After phosphorylation FTY720 modulates chemotactic responses and lymphocyte trafficking, leading to reversible lymphocyte sequestration in secondary lymphoid tissues. It is in clinical trials for the treatment of multiple sclerosis. 

Tissue-Specific Expression. In the adult rodent, PPARy is expressed in brown and white adipose tissue, and at lower levels in intestine, retina, skeletal muscle, and lymphoid organs. In human, PPARy is most abundantly expressed in white adipose tissue and at lower levels in skeletal muscle, the heart, and liver, but not in lymphoid tissues, although PPARy has been identified in macrophages in human atheromas. 

I. Atrophy of thymus and thymus-dependent lymphoid tissue in rats fed di-rr-octyltindichloride. Toxicology and Applied Pharmacology, 35(1) 63-75. 

Valent P, Horny H, Li C, et al Mastocytosis in Jatfe E, Harris N, Stein H, Vardiman J (eds) World Health Organization Classification of Tumors. Pathology and Genetics of Tumors of Hematopoietic and Lymphoid Tissue. Lyon, lARC Press, 2001, pp 293-302. 

MTX exceeds any other marine toxins known in the mouse lethality (0.13 ig/kg) and is 80 times more potent than commercial saponin (Merck) in hemolytic activity. According to Terao (72), MTX induced severe pathomorphological change in the stomach, heart and lymphoid tissues in mice and rats by i.p. injection of 200... 

Gorry PR, Bristol G, Zack JA et al (2001) Macrophage tropism of human immunodeficiency virus type 1 isolates from brain and lymphoid tissues predicts neurotropism independent of coreceptor specificity. J Virol 75 10073-10089... 

Picomaviruses Poliovirus Naked icosahedral particles 28 nm in diameter One of a group of enteroviruses common in the gut of humans. The primary site of multiplication is the lymphoid tissue of the alimentary tract. Only rarely do they cause systemic infections or serious neurological conditions like encephalitis or poliomyelitis... 

NK cells are a subset of lymphocytes found in blood and lymphoid tissues, especially the spleen. They are about 15 an in diameter, possess a kidney-shaped nucleus and have two or three large granules in the cytoplasm. They are derived from the bone marrow. NK cells have the ability to kill certain tumour lines and normal cells infected by virus. Killing by NK cells is not specific for viral antigenic epitopes, and is not restricted by MHC molecules. They do not possess CD3 but do express CD2, CD 16 and CD56, together with a low-affinity receptor for the Fc portion of IgG. 

Evasion of tolerance to self antigens. Hidden or sequestered antigens do exist, for instance spermatozoa and eye-lens tissue. These are confined to anatomical sites which do not have access to lymphoid tissue, and exposure of the above to lymphoid cells as a result of surgery or accident results in the production of the corresponding antibodies. 

PERRIN F, PERRIN P, CHAMP M, BORNE, F, MEFLAH K, MENANTEAU J (1997) Short-chain frUCtO-oligosaccharides rednce the occurrence of colon tumor and develop gut-associated lymphoid tissue in Min mice. Cancer Res. 57 225-8. 

Powell, J.J. et ah. Characterisation of inorganic microparticles in pigment cells of human gut associated lymphoid tissue. Gut, 38, 390, 1996. 

As a generalization, to be orally well absorbed a compound must be soluble in the contents of the gastrointestinal lumen [4]. Solubility in aqueous buffer is commonly used as a simpHfying surrogate for intestinal content solubility. There are rare exceptions to the principle that to be absorbed a compound must be soluble. SoHd particles, e.g. starch, can be absorbed. Absorption of very small quantities of even biologically very large compounds can occur via lymphoid tissue, e.g. orally active vaccines. Very hpophihc basic compounds, e.g. certain antimalarials, can be absorbed via the intestinal lymphatics and dehvered directly to the heart... 

BAF Basophil-activating fector BAL Bronchoalveolar lav e BALE Bronchoalveolar lavage fluid BALT Bronchus-associated lymphoid tissue... 

CAH Chronic active hepatitis CALLA Common lymphoblastic leukaemia antigen CALX Conjunctival associated lymphoid tissue CaM Calmodulin cAMP Cyclic adenosine monophosphate also knomt as adenosine 3, 5 -phosphate CAM CeU adhesion molecule CAP57 Cationic protein from neutrophils CAT Catalase CatG Cathepsin G... 

The malignant lymphomas are hematologic cancers that consist of a cluster of diseases of the lymphoid tissue. The primary malignant cells for lymphomas are lymphocytes of B-cell, T-cell, and NK-cell origin. These cells originate from a small population of... 

Lymphomas not included in Working Formulation mycosis fungoides, mantle cell lymphoma, monocytoid B-cell lymphoma, mucosa-associated lymphoid tissue (MALT), anaplastic large cell lymphoma, angiocentric lymphoma, angioimmunoblastic lymphadenopathy (AILD), Castleman s disease, adult T-cell leukemia/lymphoma. 

Gut-associated lymphoid tissue (GALT) Lymphoid tissue, including Peyer s patches, found in the gut that is important for providing localized immunity against pathogens. 

Yoneyama H, Matsuno K, Zhang Y, et al. Regulation by chemokines of circulating dendritic cell precursors, and the formation of portal tract-associated lymphoid tissue, in a granulomatous liver disease. J Exp Med 2(X)I I93(I) 35M9. 

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