Apoptosis in thymus of adult Xenopus laevis

Ruben, Laurens N.; Buchholz, Daniel R.; Ahmadi, Proochista; Johnson, Rachel O.; Clothier, Richard H.; Shiigi, Stanley M.

doi:10.1016/0145-305x(94)90015-9

Cited by 17 publications

(5 citation statements)

References 11 publications

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“…Apoptosis in X. laevis has been demonstrated using flow-cytometric visualization of DNA loss [14], in developing [15] and in adult Xenopus after exposure in vitro to glucocorticoid, lectin, or antigen [14]. In situ visualization of apoptosis in adult Xenopus, following lectin stimulation of T and B cells [16], and in the thymuses and spleens of metamorphic larval Xenopus [17], confirmed the signficance of this process in vivo in amphibia.…”

Section: Introductionmentioning

confidence: 82%

“…(table 1). Given similar responses to 10 -8 and 10 -6 M DEX (table 1), it was decided to use 10 -7 M DEX, the concentration used in two prior reports on in vitro apoptosis in this species [14,15].…”

Section: Resultsmentioning

confidence: 99%

“…During the experimental period, selective samples of phenolextracted DNA were run on agarose gels [14] to show the presence of the typical ladder of DNA fragments in multiples of 180 bp, to confirm that the loss of DNA being assayed by flow cytometry was related to apoptotic processes. Such a ladder from Xenopus cells has been published previously [14].…”

Section: Analysis Of the Resultsmentioning

confidence: 99%

“…Results of the analysis of 5,000 cells are produced as histograms, e.g. those previously published [14], where the numbers of cells with less than the normal content of DNA, as well as those with normal genomic content, are displayed. The percentage of cells with less than the genomic amount of DNA binding, the apoptotic level, was calculated.…”

Section: Flow Cytometrymentioning

confidence: 99%

“…the splenocytes were usually from 8-12 animals for each experimental condition. After the 4-hour exposure period, cells were spun at 2,000 rpm at 10°C for 5 min, twice washed with culture medium, resuspended in fresh medium and culture for 16 h. Longer exposure experiments, with similar cultures of splenocytes, were treated with the reagents, or media alone, for 20 h, as in previous protocols used to measure the modulation of apoptosis in vitro with Xenopus immunocytes [14].…”

Section: Cell Preparation and Culturementioning

confidence: 99%

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Adrenergic Modulation of Apoptosis in Splenocytes of <i>Xenopus laevis</i> in vitro

Haberfeld

Johnson²,

Ruben³

et al. 1999

Neuroimmunomodulation

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Impaired and healthy cells undergo suicide using an intrinsic genetic program. Exposure to stress-related α₂- or β-adrenergics for 4 or 20 h in vitro had no effect on apoptosis in splenocytes of adult Xenopus laevis, while a 4-hour coincubation of clonidine, an α₂-agonist, with a calcium ionophore (A23187) or a phorbol diester (PMA), enhanced apoptosis induced by each apoptogen alone. Clonidine did not affect apoptosis stimulated with dexamethasone (DEX), however. Comparable in vitro exposures to isoproterenol, a β-agonist, reduced apoptotic levels stimulated by all three apoptogens alone. Following 20 h coexposure, clonidine no longer affected A23187-induced apoptosis, but reduced PMA-induced apoptosis, while isoproterenol enhanced apoptosis stimulated with both. Neither agonist modulated apoptosis induced by 20 h of exposure to DEX. Thus, adrenergic agonists modulated apoptosis in cells coexposed to A23187 and PMA, in a time-dependent and adrenoceptor class-dependent fashion. These stress-induced products can affect concurrent apoptosis reversibly over time in vitro, and thus possibly in vivo.

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Section: Introductionmentioning

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Section: Analysis Of the Resultsmentioning

confidence: 99%

Section: Flow Cytometrymentioning

confidence: 99%

Section: Cell Preparation and Culturementioning

confidence: 99%

See 3 more Smart Citations

Adrenergic Modulation of Apoptosis in Splenocytes of <i>Xenopus laevis</i> in vitro

Haberfeld

Johnson²,

Ruben³

et al. 1999

Neuroimmunomodulation

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Conservation of Apoptosis as an Immune Regulatory Mechanism: Effects of Cortisol and Cortisone on Carp Lymphocytes

Weyts

Kemenade²,

Flik

et al. 1997

Brain, Behavior, and Immunity

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This is the first study to show that apoptosis as an immune regulatory mechanism is conserved in fish, demonstrating its importance in maintaining immunological homeostasis. The data further show that this mechanism is subject to control by glucocorticosteroids. Carp plasma cortisol concentrations increase from 20 to 434 ng/ml and cortisone from 5 to 50 ng/ ml within 9 min o f the onset o f handling stress. At basal steroid concentrations in vitro, cortisol, but not its conversion product cortisone, inhibits proliferation o f peripheral blood lymphocytes (PBL), as measured by [3H]thymidine incorporation. Induction of apoptosis in activated PBL is the apparent mechanism o f cortisol action. In nonstimulated PBL cultures, apoptosis is induced by neglect (a lack o f stimulating signals). Stimulation with LPS or PHA rescues lymphocytes from this type of apoptosis. Stimulated PBL populations, however, are sensitive to cortisol-induced apoptosis. Culture supematants from activated PBL protect PBL from apoptosis by neglect, probably by supplying a growth signal. These supematants, how ever, have no effect on cortisol-induced apoptosis.

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The time course, localization and quantitation of T- and B-cell mitogen-driven apoptosis in vivo

et al. 1995

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Apoptosis in thymus of adult Xenopus laevis

Cited by 17 publications

References 11 publications

Adrenergic Modulation of Apoptosis in Splenocytes of <i>Xenopus laevis</i> in vitro

Adrenergic Modulation of Apoptosis in Splenocytes of <i>Xenopus laevis</i> in vitro

Conservation of Apoptosis as an Immune Regulatory Mechanism: Effects of Cortisol and Cortisone on Carp Lymphocytes

The time course, localization and quantitation of T- and B-cell mitogen-driven apoptosis in vivo

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