Thymus cells

Penninks Seinen (1980) looked at subcellular distribution of dibutyltin in rat liver and thymus cells in vitro. Radioactivity was concentrated in mitochondria and low in cytoplasm in thymus cells, in marked contrast to liver cells, where mitochondrial radioactivity was very low. Differences in cellular distribution have been suggested as a reason for the selective effect on the thymus. 

The antilymphocyte globulin is obtained through the immunization of horses with human lymphoid cells or with fetal thymus cells. The antilymphocyte antibody destroys the T cells and impairs delayed hypersensitivity and cellular immunity without altering humoral antibody formation. The pattern of immunosuppression obtained with antilymphocyte globulin is identical to that brought about following thoracic duct drainage that depletes the numbers of small lymphocytes. 

CD4 (cluster of differentiation 4) glycoprotein, a co-receptor of the T (thymus) cell receptor... 

Rooney A, Fournier M, Bernier J, Cyr D (2003) Neonatal exposure to propylthiouracil induces a shift in lymphoid cell sub-populations in the developing postnatal male rat spleen and thymus. Cell Immunol, 223 91-102. 

Chiba K, Matsuyuki H, Maeda Y, Sugahara K. Role of sphin- 189. gosine 1-phosphate receptor type 1 in lymphocyte egress from secondary lymphoid tissues and thymus. Cell Mol. Immunol. 2006 3 11-19. 

The three-dimensional structure of IL-7 is not known, but it is a member of the four a-helical short-chain cytokine family (152AA). It stimulates early B- and T-lymphocyte growth and the proliferation and differentiation of mature T cells, which are produced by stromal marrow and thymus cells. IL-7 can be classified as a CSF. ... 

Dibenzodioxins, including TCDD (dioxin), have been demonstrated to cause severe thymic atrophy with resulting effects on the immune system. The target seems to be the epithelial cells in the thymus, and it is interesting that thymus cells contain the TCDD receptor. Thymic atrophy correlates with the presence of this receptor, and other compounds which compete with TCDD for this receptor also cause thymic atrophy. The basis of the toxicity of TCDD to the thymus may be an effect on T-cell maturation and differentiation. The result of exposure of animals to TCDD is depressed antibody responses, increased susceptibility to infectious agents, and depressed T-cell function. In humans exposed to TCDD occupationally, decreased serum levels of some immunoglobulins and depressed lymphocyte responses to mitogens were reported. 

Olgun et al. (2004) Mouse Lindane, malathion, permethrin Exposure of thymus cells to combinations of chemicals resulted in significantly higher levels of apoplo.si.s and necrosis... 

Ginsenoside Rgl (27) from Panax ginseng also exerted a direct mitogenic effect when applied in vitro to microcultures of thymus cells. Again, this effect was greater with a lower dose (25 pg/ml) while a higher dose of Rgl (50 pg/ml) had no significant effect on thymocytes [59]. 

Similar results had previously been obtained by a group of Russian workers for the activation of the tyrosine/tyrosinase system by X- or y-irradiation and o-diphenols and o-quinones were formed as a result of the radiation [95]. When nuclei from rat thymus cells were incubated with the irradiated tyrosine-tyrosinase system, it was shown spectroscopically that the o-quinones produced were almost completely absorbed by the nuclei. In other experiments, it was observed that these quinones were adsorbed by high molecular weight DNA. Quinones were also detected in extracts from irradiated potato tubers and a fraction containing these quinones was obtained a chromatographic... 

Further studies by Williams et al. (1979) with a battery of mitogens showed that response to the T-cell mitogen Con A was also depressed in spleen cells while depressed responsiveness to PHA and PWM was seen in thymus cells (Table VII). It remains unclear whether the gestation or lactation period is the most critical. 

Fig. 61 a-d. Tissue specificity of isolated nuclei and chromatin template activity, a RNA synthesized by the isolated thymus cell nuclei was hybridized with DNA in the presence of nonlabeled competide RNA of other origin. The thymus RNA is the more effective competitor than RNA obtained from heterologous tissues, b RNA extracted from liver is the most effective competitor in the hybridization reaction between DNA and RNA synthesized by liver chromatin in in vitro condition, c Experiment as above with RNA from kidney, d Kinetics of hybridization to calf thymus DNA of H RNA s made with the following primers whole calf thymus chromatin ( — — —) deproteinized chromatin (o —o —o —) dehistoned chromatin (a —A —a —) and DNA. 7, E. coli 2, brain 3, kidney 4, liver 5, spleen 6 thymus. (After Paul and Gilmour, 1968)... 

In Table 4 frequencies of precursor cells from non-immunized mice are compiled (see also Fig. 3). Some authors used spleen cells for limiting dilutions, others bone marrow cells in combination with a constant number of thymus cells. The latter, which guarantees that B cells are titrated, was used by Cudkowicz et al. (1969, I970) and Miller and Cudkowicz (1970). Further-... 

In one experiment, where 1.2% fluorescent cells were present in the unseparated cell suspension, the separation procedure enriched in the deflected fraction the percentage of fluorescent cells to 70% and depleted in undeflected fraction to <0.2%. The adoptive transfer experiment showed that 3 X 10 unseparated cells gave an anti-KLH titer 4.6(log2), 3 X 10 undeflected fraction gave a barely detectable response, titer 1 (logg), and 5 X 10 deflected cells mixed with 90X10 thymus cells yield an anti-KLH-titer 2.3 (thymus cells alone gave no response). 

It has been shown (for review see Du Pasquier, 1973) in studies with tadpoles, that the first antibody response could be detected in spleens containing 10 cells. A small larvae of Xenopus laevis at 4 weeks of larval life may have about half a million lymphocytes, from which (if thymus cells, immature cells and T cells are subtracted) not more than 100000 lymphocytes might be presursors of antibody-forming cells. Are these 100000 cells able to cope with the whole spectrum of immunogenic determinants which an animal of this size may encounter ... 

Shearer, G. M., Cudkowicz, G. Cellular differentiation of the immune system of mice. III. Separate antigen-sensitive units for different types of anti-sheep immunocytes formed by marrow-thymus cell mixtures. J. exp. Med. 129, 935-951 (1969). 

The extensive lymphoid circulation found in mammals complicates studies of thymus cell function. Clearly, cells can get in and out of the thymus after birth (cf. Yoffey et al., 1959 Harris and Ford, 1964 Linna and Stillstrom, 1966 Galton and Reed, 1966 Toro and Ol, 1967). This fact makes studies involving thymus cell function in immunological reactions difficult to interpret (e.g., Cohen et al., 1963 Yunis et al, 1964 Csaba et al, 1965 Davies et al, 1967). 

Cohen, M. W., Thorbecke, G. J., Hochwald, G. M., and Jacobson, E. B. (1963). Induction of graft-versus-host reaction in newborn mice by injection of newborn or adult homologous thymus cells. Froc. Soc. Exptl. Biol. Med. 114, 242-244. 

Taylor, R. B. (1963). Immunological competence of thymus cells after transfer to thymectomized recipients. Nature 199, 873-874. 

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