Thymocyte

Anti thymocyte globulin Antitrypsin Anti tuberculin agents Antitumor activity... 

CJ-Receptors are localized ia the brain stem and limbic stmcture, regions associated with endocrine function (76). In the periphery, CJ-receptors are found in the Hver, heart, ileum, vas deferens, and on lymphocytes and thymocytes. Although there is insufficient evidence to clearly define the functional role of CNS CJ-sites, based on the effects of PCP and the interaction of haloperidol with CJ-sites, CJ-receptor ligands may be antipsychotics or used for the treatment of substance abuse. Several CJ-receptor ligands have shown neuroprotective effects in vivo. Ifenprodil (315) and CNS 1102 (316) are being developed for treatment of stroke (Table 18). 

Reconstitution of T-ceU deficiencies with thymic hormones has not been successhil even though the various hormone preparations induce prothymocyte differentiation and functions of mature T-ceUs. They do not regulate the maturation of thymocytes in the thymus. In contrast, IL-2, endotoxin, thymic epithehal cell products, but not interleukin 1, were found to promote functional maturation of immature thymocytes. Two classes of dmgs show thymomimetic actions (Table 2). Levamisole [14769-73-4], sodium salt of diethyl dithiocarbamate (imuthiol) and certain... 

One vitamin E analogue, TROLOX, inhibits radiation-induced apoptosis in murine thymocytes (26). Chicks given vitamin E prior to exposure to a sublethal dose (2.25 Gy (225 rad)) of y-radiation demonstrate a more rapid recovery from damage to the thymus (100). 

Administration of dipyridamole-AMP to mice 5—25 min after 1 Gy (100 rad) of TBI y-kradiation is also protective, as indicated by plasma thymidine levels and the amount of saline soluble polynucleotides in the thymus (112). Adding dipyridamole-AMP to in vitro kradiated suspensions of thymocytes enhances the rejoining of DNA strand breaks (112). These post-kradiation effects ate presumably mediated by the activation of extraceUulat adenosine receptors. 

Pepin et al. (1992) generated transgenic mice in which antisense RNA complementary to GR cDNA led to reduced expression mostly in neuronal tissues. Consequently, this was found to result in an impaired behavior, a defective response to stress as well as in obesity. King et al. (1995) generated transgenic mice where reduced GR expression was limited to the thymus. This leads to an altered thymocyte development, changes in the T-cell repertoire, and a reduced risk to develop autoimmune diseases. 

Radu CG, Cheng D, Nijagal A et al (2006) Normal immune development and glucocorticoid-induced thymocyte apoptosis in mice deficient for the T-cell death-associated gene 8 receptor. Mol Cell Biol 26 668-677... 

Induction of apoptosis has been reported in various mammalian cell lines. In previous studies, it has been reported that TBT induces apoptosis in isolated thymocytes at concentrations which are relevant to those causing thymus atrophy in vivo. TBT can also induce apoptosis in PC12 cells, and in human T-lymphoblastoid CEM cells. While the mechanism of TBT-induced apoptosis is still unknown, it has been reported that TBT stimulates thymocyte apoptosis by a mechanism independent of protein synthesis and under conditions where intracellular ATP levels are severely depleted. ... 

The higher molecular weight organotin(IV)s, such as TBT and TFT, are known to be immunotoxic and to cause renal and hepatic damage. TBT at environmentally relevant concentrations increases intracellular concentration of Ca(II) ([Ca(II)],) in murine thymocytes by increasing membrane Ca(II) permeability and... 

Okada et al. examined the effects of TBT on cellular content of glutathione (GSH) in rat thymocites using a flow cytometer and 5-chloromethylfluorescein diacetate, a fluorescent probe for monitoring the change in the cellular content of GSH. TBT at nanomolar concentrations reduced the cellular content of GSH. There is an important implication on the TBT-induced depletion of cellular GSH since GSH has an important role in protecting the cells against oxidative stress and chemical and metal intoxications. TBT-induced decrease in cellular content of GSH in thymocytes may increase the vulnerability of the immune system. ° ... 

Rat DOTC 6 weeks (maies), 1-28 days (femaies) at 0, 50, or 150 mg/kg diet = 0, 2.5, and 7.5 mg/kg body weight Decreased weight of thymus iymphocyte depiction in thymus and thymus- dependent areas of spieen and iymph nodes decrease of number and viabiiity of nucieated thymocytes Lowest dose at which effects were reported = 2.5 Seinen Wiiiems (1976)... 

Various findings together suggest that organotins may have an effect at the level of the cell membrane and/or cytoskeleton, resulting in disturbances of inter-and intracellular communication processes, which are of crucial importance to thymocyte maturation (Pieters et al., 1994a). 

In vivo and in vitro studies on the differentiation and proliferation of immature rat thymus subsets have shown that dibutyltin dichloride reduces the production of CD4 CD8 and mature single-positive thymocyte proliferation by selectively inhibiting immature CD4 CD8 thymocyte proliferation but without affecting the differentiation capacity of these cells, suggesting that thymocyte proliferation and differentiation are separately regulated processes (Pieters et al., 1993, 1994a,b, 1995). 

Pieters RHH, Bol M, Lam BW, Seinen W, Bloksma N, Penninks AH (1993) Recovery from chemically induced thymus atrophy starts with CD4- CD8- CD2(high) TcR alpha-beta-(low) thymocytes and results in an increased formation of CD4- CD8- TcR-alpha-beta(high) thymocytes. Immunology, 78(4) 616-622. 

Pieters RHH, Bol M, Penninks AH (1994b) Immunotoxic organotins as possible model compounds in studying apoptosis and thymocyte differentiation. Toxicology, 91 (2) 189-202. 

Pieters RHH, Bol M, Ariens T, Punt P, Seinen W, Bloksma N, Penninks AH (1994c) Selective inhibition of immature CD4-CD8+ thymocyte proliferation, but not differentiation, by the thymus atrophy-inducing compound di-rvbutyltin dichloride. Immunology, 81(2) 261-267. 

Pieters RHH, Albers R, Bleumink R, SnoeiJ NJ, Itoh T, Seinen W, Penninks AH (1995) The thymus atrophy-inducing organotin compound DBTC inhibits the binding of thymocytes to thymic epithelial cells. International Journal of Immunopharmacology, 17(4) 329-337. 

A second explanation of the ability of oxidative stress to cause DNA damage is that the stress tri ers a series of metabolic events within the cell that lead to activation of nuclease enzymes, which cleave the DNA backbone. Oxidative stress causes rises in intracellular free Ca, which can fiagment DNA by activating Ca -dependent endonucleases (Orrenius etal., 1989 Farber, 1990 Ueda and Shah, 1992) in a mechanism with some of the features of apoptosis (see Wyllie, 1980). An example of apoptosis is the killing of immature thymocytes by glucocorticoid hormones, which activate a cell-destructive process that apparently involves DNA fragmentation by a Ca -dependent nuclease. 

Wyllie, A.H. (1980). Clucocorticoid-induced thymocyte apoptosis is associated with endcgenous endonuclease activation. Nature 284, 555-556. 

CDla Isoform a also known as non-classical MHC class I-like surface antigen present on thymocytes and dendritic cells... 

CD lb Known to be present on thymocytes and dendritic cells CDlc Isoform c also known as non-classical MHC class I-like surface antigen present on thymocytes CD2 Defines T cells involved in antigen non-specific cell activation CD3 Also known as T cell receptor-associated surface glycoprotein on T cells CD4 Defines MHC class Il-restricted T cell subsets... 

Muronomab-CD3 (OKT-3) is a murine monoclonal antibody that targets the CD3 receptor. The CD3 receptor is only found on activated T cells and medullary thymocytes.10,11,14 After binding with the CD3 receptor, complement-mediated T cell lysis occurs rapidly. This agent is dosed at 5 mg/day. This dose is given daily for 10 to 14 days. Lower doses have been used successfully in liver transplant recipients.14... 

CCR9 Memory T cells, B cells, immature thymocytes TECK/CCL25 Yes ND... 

Vielkind S, Gallagher-Gambarelli M, Gomez M, Hinton HI, Cantrell DA. Integrin regulation by RhoA in thymocytes. J Immunol 2005 175(l) 350-357. 

Thymus CXCR4 Progenitor entry and/or localization of DN thymocytes... 

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