Age-Related Changes in G&lt;sub&gt;0&lt;/sub&gt;-G&lt;sub&gt;1&lt;/sub&gt; Transition and Proliferative Capacity of Mitogen-Stimulated Murine Spleen Cells

Joncourt, F.; Kristensen, F.; Weck, A.L. de

doi:10.1159/000212545

Cited by 6 publications

(2 citation statements)

References 7 publications

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“…Flow cytometric analysis of cells stained with acridine orange for rRNA content showed that a larger population of lymphocytes from young than aged mice entered cell cycle after 40 h incubation with Con A and rIL-2 (data not shown). This is in agreement with previous studies using unseparated peripheral blood lym- phocytes from humans stimulated with PHA and spleen cells from NMRI mice activated with Con A or PHA (Joncourt et al, 1982;Staiano-Coico et al, 1984).…”

Section: Effects Of Cytochalasins On Proliferation Of Activated Go T supporting

confidence: 93%

Differential regulation of actin polymerization following activation of resting T lymphocytes from young and aged mice

Brock

Chrest

1993

Journal Cellular Physiology

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Actin polymerization accompanies receptor-mediated responses and is correlated with motility-related events. In T lymphocytes, there is a lateral redistribution of surface receptors into caps and aggregation of actin-myosin in cytoplasmic subcaps, and these are impaired in T cells from aged individuals. This study documents marked changes in age-related cytoskeletal actin filament function which may account for the reduced motility. Basal levels of filamentous actin (F-actin) are significantly higher in purified G(o) T cells from aged C57BL/6 mice, due to a preferential increase in the CD8+ subpopulation. Following activation of the resting T cells with Concanavalin A (Con A), F-actin depolymerized in cells from young mice for 2 min, followed by rapid polymerization, reaching a plateau 200% above resting levels. In cells from 15-17-month-old mice, an attenuated depolymerization phase was seen for 45 sec, followed by little polymerization. No depolymerization or polymerization phases occurred in cells from aged mice. Phorbol 12 myristate 13-acetate (PMA), which activates protein kinase C (PKC), bypassing receptor mediated signals, induced actin polymerization to 57% of the levels of that after Con A stimulation in cells from both young and old animals and partially eliminated the differences in actin filament assembly due to age. Perturbation of the cytoskeleton with cytochalasin E (CE) potentiated proliferation of Con A-stimulated T cells from aged mice but did not completely restore the deficit attributed to immunosenescence. The results show an age-related impairment of cytoskeletal functions and suggest that differences in early signal transduction events contribute to the decrements in surface receptor motility and subsequent proliferation of T lymphocytes from older individuals.

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Section: Effects Of Cytochalasins On Proliferation Of Activated Go T supporting

confidence: 93%

Differential regulation of actin polymerization following activation of resting T lymphocytes from young and aged mice

Brock

Chrest

1993

Journal Cellular Physiology

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“…Thus, we have shown that with age a reduced number of lymphocytes [peripheral blood lymphocytes (PBL) in human or spleen cells in mice] can be activated (undergo Go-G| transition) by concanavalin A (Con A) or phytohemagglu tinin (PHA) [7], Furthermore, in aged indi viduals the interleukin 2 (IL2)-dependent event within the Gi phase (G]a-G ib transi-tion) docs not take place in all activated (G|a) cells. This is due possibly to a decrease in IL-2 production [8], Gia-Gib transition, how ever, is not improved even in cultures where IL-2 is readily available, e.g., through addi tion of exogenous IL-2 [8], Since the signal given by IL-2 is known to be transmitted via specific receptors appearing on the surface of activated cells [2], this suggested that regula tion of the level of IL-2 and possibly other receptors may contribute to the age-related impairment of the T-cell response.…”

Section: Introductionmentioning

confidence: 99%

Age-Related Changes in the Formation of Glucocorticoid and Insulin Receptors during Lectin-Induced Activation of Human Peripheral Blood Lymphocytes

Joncourt¹,

Wang²,

Kristensen³

et al. 1985

Gerontology

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The influence of age on the number of receptors for insulin and glucocorticoids on human T cells was examined. The specific binding of ¹²⁵I-insulin and ³H-dexamethasone to phytohemagglutinin-(PHA)-stimulated T cells was found to decrease with age. Populations of PHA-stimulated T cells, however, are heterogeneous with respect to cell cycle phases, and cells in different cell cycle phases have been shown to bear different numbers of receptors. Therefore, it was not clear whether the measured decrease in specific binding in cultures from aged donors was due to a decreased number of activated cells or to a decreased number of binding sites per cell. In parallel to measurements of receptors, performed at different times following stimulation (20 and 44 h), numbers of cells in the different early cell cycle phases G₀, G_1a and G_1b were quantitated by flow cytometry. In this way the receptor number per cell in each phase of the cell cycle could be determined. Receptor numbers on resting cells and in the earliest phase of activation (G_1a) were found not to be influenced by age. A decreased receptor density, however, was apparent on G_1b cells from aged donors.

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Lymphocyte Proliferation, Lymphokine Production, and Lymphocyte Receptors in Aging

Weck

Kristensen

Joncourt

et al. 1984

Thymic Hormones and Lymphokines

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Age-Related Changes in G<sub>0</sub>-G<sub>1</sub> Transition and Proliferative Capacity of Mitogen-Stimulated Murine Spleen Cells

Cited by 6 publications

References 7 publications

Differential regulation of actin polymerization following activation of resting T lymphocytes from young and aged mice

Differential regulation of actin polymerization following activation of resting T lymphocytes from young and aged mice

Age-Related Changes in the Formation of Glucocorticoid and Insulin Receptors during Lectin-Induced Activation of Human Peripheral Blood Lymphocytes

Lymphocyte Proliferation, Lymphokine Production, and Lymphocyte Receptors in Aging

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