Lymphocyte, source

The spleen serves as a rich source of lymphocytes. The spleen is the source used most often as it is easily obtainable. Lymph nodes and peripheral blood are also occasionally used as lymphocyte sources. In humans, peripheral blood is often the only source used, unless the spleen or some lymph nodes were being surgically removed (and thus available). 

Despite the differences between the naivety of different lymphocyte sources, it is still not clear which source (more or less naive) provides the best... 

Non-immune libraries are produced in a similar fashion, but using B-lymphocytes fromnon-im-munized donors as a source of antibody genes. This approach becomes necessary if initial immunization with the antigen of interest is not possible (e.g. due to ethical considerations). Although such... 

Catecholamines from non-neuronal intracellular and extracellular sources can interact with cells of the immune system. Recently, NE and EPI that can be released by activating stimuli have been detected in lymphocytes and macrophages [reviewed in 2], These cells may synthesize catecholamines and/or take up and store catecholamines from extracellular sources (i.e., NE released from sympathetic nerves or NE and EPI present in the plasma). 

GM-CSF is undetectable in the serum of normal humans, and no normal cells have been shown to express this protein constitutively. Some transformed cells may constitutively express GM-CSF, and it is actively synthesised and secreted by antigen- and lectin-stimulated T cells and by endothelial cells and fibroblasts exposed to TNF, IL-1 or endotoxin. Other sources of GM-CSF include stimulated B lymphocytes, macrophages, mast cells and osteoblasts, whilst TNF and IL-1 can stimulate its production by acute myeloid leukaemia cells. Some solid tumours and synovial cells from rheumatoid joints may also express GM-CSF and this may be important in disease pathology. 

Tumour necrosis factor (TNF) was originally described as a factor produced following exposure of Bacille-Calmette-Guerin-treated animals to bacterial endotoxin. It was so named because it possessed the ability to necrotise tumours. This factor is now named TNF-a to distinguish it from another, related cytokine lymphotoxin, which is sometimes referred to as TNF-/J Alternative names for TNF-a include cachectin and cytotoxin. Its primary cellular source in the body is the activated macrophage, but some other cell types (e.g. NK cells, astrocytes, some lymphocytes, fibroblasts, many tumour cells, endothelial cells and neutrophils) have also been shown to synthesise this cytokine. 

The classical cellular sources of histamine are mast cells and basophils, gastric enterochromaffin-like cells, platelets and histaminergic neurons. Interestingly the cells in the immune system, which do not store histamine, show high HDC activity and are capable of production of high amounts of histamine, which is secreted immediately after synthesis [20]. These cells include platelets, monocytes/macrophages, DCs, neutrophils, and T and B lymphocytes. 

Lymphocytes from other sources (e.g., lymph nodes, etc.) are not feasible to use because of their low RNA yield and the large amount of RNA needed for the array experiments. 

Cultured cells (from human peripheral blood lymphocytes or from Syrian hamster embryo (SHE)) or cell lines (CHO, V79, CHL/IU, L5178 Y) are exposed to the test substances both with and without an exogenous source of metabolic activation unless primary cells with metabolizing capability are used. After exposure to the test substance, cell cultures are grown for a sufficient period to... 

Production of blood cells in bone marrow of the central axial skeleton is referred to as medullary hematopoiesis. Hematopoietic tissue in adult bone marrow is well perfused and contains fat cells (adipocytes), and various types of blood and blood precursor cells encased within a protein matrix. Fibroblast, stromal and endothelial cells within bone marrow, serve as sources of matrix proteins as well as a factory for growth factors and chemokines that regulate blood cell production and release matured cells into the circulation [2,3]. Chemokines act as signal lamps for trafficking of lymphocytes in and out of lymphoid tissues. Erythroblasts, neutrophils, lymphoblasts, macrophages, megakaryocytes, and pluripotent stem cells are also found within the calcihed lattice crisscrossing the marrow space. 

A new nomenclature was therefore designed to describe the subtypes of IFN rather than naming them for the source from which they were originally isolated. The designation of huIFN-a was suggested for the major class of IFNs present in leukocyte or lymphoblastoid preparations. huIFN-P was used to denote IFN produced by fibroblasts, and huIFN-y was assigned to human immune IFN produced by activatedT-lymphocytes [25] (Table 7.2). 

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