T-cells subtypes

It is established today that a set of T-regulatory cells (Tregs) as well as other T-cell subtypes are... 

Figure 3.8 CD4 differentiation. The open arrows indicate those stimuli that support and the grey arrows those that inhibit the growth and differentiation of T cell subtypes.

The primary functions of lymphocytes are to control and be the effector cells for the immune system. Many of these cells also are important synthetic sites for various cytokines. Lymphocytes can be functionally divided into cells that display cell-mediated immunity (T cells) and those that are responsible for humoral immunity (B cells Table 98-2). Several different T-cell subtypes are found in peripheral blood. These include the cytotoxic suppressor T cells (CDS), which attack intracellular pathogens and regulate the size and duration of the immune response, as well as helper T cells (CD4). The latter cells are responsible for delayed hypersensitivity, stimulation of B-ceU differentiation (maturation), and antibody production, in addition to regulation of inflammatory reactions. B lymphocytes ultimately become plasma cells, which produce immunoglobulin specific for an antigen attached to the cell s surface. 

Mouse None 3 ppm in water Altered B-cell and T-cell subtypes decreased GSH concentrations in splenocytes Thompson et al. 1998... 

CD4+CD25+ T cells. Subtype of regulatory CD4+ T cells with potential role in the regulation of the immune homeostasis. Seems to be important in preventing the development of autoimmune diseases (depletion leads to the spontaneous development of various autoimmune diseases in genetically susceptible animals transfer prevents the development of organ-specific autoimmunity). 

CCL22) are not found in sarcoidosis (145). CCL18, a chemokine without known receptor, was either not detected (146) or was found only in patients with advanced chest X-ray types (147) suggesting that this chemokine is related to fibrosis. Although this chemokine is thought to be responsible for chemotaxis of lymphocytes, no association wither either T-cell subtype was observed. 

Protein kinase B, or Akt, was discovered as the product of an oncogene of the acutely transforming retrovirus AKT8, causing T-cell lymphomas in mice. It encodes a fusion product of a cellular serine/threonine protein kinase and the viral structural protein Gag. This kinase is similar to both protein kinase Ce (PKCe 73% identity to the catalytic domain) and protein kinase A (PKA 68%). It differs from other protein kinases in that it contains a pleckstrin homology (PH) domain, which allows it to bind to polyphosphoinositide head groups (and also to G-protein fly subunits). To date, three subtypes have been identified a, (3, and y, all of which show a broad tissue distribution. It... 

Importantly, although Th2 cells are responsible for the development of allergic diseases, Thl cells may contribute to chronicity and effector phase in allergic diseases [30-33,38,39]. Distinct Thl and Th2 2 subpopulations of T cells counterregulate each other and play a role in distinct diseases [34,35]. In addition, recent studies have demonstrated that peripheral T-cell tolerance is crucial for a healthy immune response and successful treatment of allergic disorders [40-42]. A further subtype ofT cells, with immunosuppressive function and cytokine profiles distinct from either Thl and Th2 cells, termed regulatory/suppressor T cells (Treg), has been existence in humans has been demonstrated [41,... 

Shimoyama, M., Diagnostic criteria and classification of clinical subtypes of adult T-cell leukemia-lymphoma. A report from the Lymphoma Study Group (1984-87). Br. J. Haematol. 79,428-437 (1991). 

Brambilla P, Bellodi L, Perna G, Garberi A, Panerai A, Sacerdote P (1993) T cell cholecystokinin concentrations in panic disorder. Am J Psychiatry 150 1111-1113 Briggs AC, Stretch DD, Brandon S (1993) Subtyping of panic disorder by symptom profile. Br J Psychiatry 163 201-209... 

Lymphocytes are one of the primary cell types involved in the immune response. There are two general types of lymphocytes, B and T. Both are derived from bone marrow lymphoid stem cells, but T cells go through an additional maturation process in the thymus. Although the morphology of T cells and B cells is similar, the functions of these two types are distinct. After antigen exposure, B cells develop into antibody-producing plasma cells, whereas T cells are divided into functional subtypes that possess distinct cell surface antigens. 

The direct effects opioid and opioidlike peptides exhibit on cells of the immune system is both varied and, in some instances, contradictory, depending on which receptor subtype is being studied. Mu and kappa receptors generally affect immunofunction in a suppressive manner, where delta receptors tend to express immunostimulation [82-85]. However, selected delta antagonists have shown to elicit suppressive effects on B-cell proliferation, NK cell activity, and T-helper cell cytokine production [86]. The alteration of leukocyte function via opioid receptors will be discussed highlighting specific cell subtype immunomodulation. Endorphin shows a inhibitory effect on splenocyte proliferation through central and peripheral autocrine/paracrine pathways [87]. 

Loweth et al. [120] showed that fluoride induces apoptosis in clonal pancreatic fi cells and in the cells of normal rat islets of Langerhans. The process may reflect the formation of AlF41 since it was inhibited by the aluminum chelator desferrioxamine. Recent studies provide evidence that apoptosis of pancreatic fi cells is important in the early etiology of diabetes mellitus. Treating thymus lobe cells with aluminofluoride complexes also provoked apoptosis of a wider range of thymocyte subtypes [121] with an accumulation of inositol phosphates. The responses to aluminofluoride complexes were not prevented by inhibitors of tyrosine kinases, suggesting that unidentified G-proteins which couple to phospholipase C activation may also be capable of initiating apoptosis by a route independent of the T cell receptor. 

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