Permissive effect of cytochalasin B on DNA synthesis in concanavalin-A-treated lymphocytes

1984 ◽  
Vol 66 (1) ◽  
pp. 155-166
Author(s):  
K.G. Sundqvist ◽  
L. Wanger ◽  
W. Ensgstom
Keyword(s):  
Dna Synthesis ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
Human Lymphocytes ◽  
Initial Period ◽  
Culture Conditions ◽  
Plant Lectins ◽  
Conventional Culture ◽  
Per Se ◽  
Suppressive Action

Unfractionated or T-cell-enriched human lymphocytes can be stimulated to undergo DNA synthesis and mitosis by the addition of polyclonal cell activators such as the plant lectins phytohaemagglutinin and concanavalin A (ConA). Under conventional culture conditions stimulated cells cease proliferating only a few days after the first cells have initiated DNA synthesis. Cytochalasin B (CB), which is non-mitogenic per se, causes a prolongation of the period during which ConA stimulates DNA synthesis from normally 3–5 days to more than 3 weeks. The CB-induced prolongation of cell proliferation is clearly stage-specific in the sense that the CB effects are exerted after an initial period of 24 h and do not come into effect until 48 h after onset of ConA stimulation. In contrast, CB exerts a slight suppressive action on DNA synthesis between 24 h (when activated cells initiate DNA synthesis) and 48 h after onset of stimulation. These two separate effects of CB, i.e. augmentation of lymphocyte stimulation 48 h after stimulation, and suppression of stimulation before this point of time, are relatively independent of the concentration of CB.

scholarly journals TP53-Induced Glycolysis and Apoptosis Regulator (TIGAR) Is Upregulated in Lymphocytes Stimulated with Concanavalin A

2021 ◽  
Vol 22 (14) ◽  
pp. 7436
Author(s):  
Helga Simon-Molas ◽  
Xavier Vallvé-Martínez ◽  
Irene Caldera-Quevedo ◽  
Pere Fontova ◽  
Claudia Arnedo-Pac ◽  
...  
Keyword(s):  
Concanavalin A ◽  
Carbon Flux ◽  
Human Lymphocytes ◽  
Tumor Development ◽  
Pentose Phosphate ◽  
Akt Signaling Pathway ◽  
G6pdh Activity ◽  
Physiological Conditions ◽  
Glucose 6 Phosphate Dehydrogenase

The glycolytic modulator TP53-Inducible Glycolysis and Apoptosis Regulator (TIGAR) is overexpressed in several types of cancer and has a role in metabolic rewiring during tumor development. However, little is known about the role of this enzyme in proliferative tissues under physiological conditions. In the current work, we analysed the role of TIGAR in primary human lymphocytes stimulated with the mitotic agent Concanavalin A (ConA). We found that TIGAR expression was induced in stimulated lymphocytes through the PI3K/AKT pathway, since Akti-1/2 and LY294002 inhibitors prevented the upregulation of TIGAR in response to ConA. In addition, suppression of TIGAR expression by siRNA decreased the levels of the proliferative marker PCNA and increased cellular ROS levels. In this model, TIGAR was found to support the activity of glucose 6-phosphate dehydrogenase (G6PDH), the first enzyme of the pentose phosphate pathway (PPP), since the inhibition of TIGAR reduced G6PDH activity and increased autophagy. In conclusion, we demonstrate here that TIGAR is upregulated in stimulated human lymphocytes through the PI3K/AKT signaling pathway, which contributes to the redirection of the carbon flux to the PPP.

scholarly journals SELECTIVE TRIGGERING OF HUMAN T AND B LYMPHOCYTES IN VITRO BY POLYCLONAL MITOGENS

1974 ◽  
Vol 140 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Melvyn Greaves ◽  
George Janossy ◽  
Michael Doenhoff
Keyword(s):  
B Cells ◽  
B Lymphocytes ◽  
Human Lymphocytes ◽  
Culture Conditions ◽  
Pokeweed Mitogen ◽  
Cell Populations ◽  
T And B Cells ◽  
Activated T Cells ◽  
Lymphocyte Responses

Human lymphocytes from spleen and tonsils have been cultured with a variety of polyclonal mitogens. Cultures consisted of either unseparated T and B cells or alternatively purified T or B lymphocytes. The purity of the starting cell populations and the origin of activated lymphoblasts was analyzed with a panel of seven markers which discriminate between T and B cells. The selectivity of the lymphocyte responses was influenced by cell populations in a given culture, the mitogen used, and to a limited extent on culture conditions. Purified T lymphocytes from tonsil and spleen responded to phytohemagglutinin (PHA), pokeweed mitogen (PWM), and staphylococcal enterotoxin B (SEB). Purified B cells from spleen responded well to PWM, weakly to SEB and lipopolysaccharide, but not at all to PHA. Tonsil B cells responded weakly to PWM and SEB but not to PHA. Some B lymphocytes do respond to PHA in the presence of activated T cells. These results are discussed in relation to previously reported selective responses of human cells and parallel studies in animal species.

Induction of Immunoglobulin Secretion and DNA Synthesis in Human Lymphocytes in Vitro by Cytomegalovirus Preparations

2006 ◽  
Vol 24 (3) ◽  
pp. 273-281 ◽  
Author(s):  
O. RINGDÉN ◽  
T. PAULIN ◽  
V. A. SUNDQVIST ◽  
B. WAHREN ◽  
P. PIHLSTEDT
Keyword(s):  
Dna Synthesis ◽  
Human Lymphocytes ◽  
Immunoglobulin Secretion

Changes in lectin-mediated agglutinability during primary embryonic induction in the amphibian embryo

Development ◽  
1980 ◽  
Vol 57 (1) ◽  
pp. 95-106
Author(s):  
Francisco D. Barbieri ◽  
Sara S. Sánchez ◽  
Enrique J. Del Pino
Keyword(s):  
Cell Surface ◽  
Concanavalin A ◽  
Cytochalasin B ◽  
The Other ◽  
Embryonic Induction ◽  
Potassium Oxalate ◽  
Amphibian Embryo ◽  
Structural Alterations ◽  
Significant Difference ◽  
Primary Embryonic Induction

The present study was undertaken to investigate structural alterations at the surfaceof presumptive neural cells after primary embryonic induction. For this purpose, plant lectinmediated agglutinability of dissociated cells from the epiblast of Bufo arenarum gastrulae was tested. Two fragments of epiblast were excised from the same mid-gastrula: one from the dorsal side of the egg, making contact with the invaginating chordamesoblast and assumed to be composed of determined cells and the other from the ventral region of the egg, facing the blastocoele cavity and assumed to be composed of undetermined cells. Cells of the pooled fragments were dissociated in calcium-free Holtfreter's solution with potassium oxalate and incubated in the presence of different concentrations of phytohemagglutinin and concanavalin A. Epiblast cells overlying the archenteron roof are less agglutinated with both lectins than undetermined cells. On the other hand, when egg fragments were removed from the dorsal and ventral regions of early gastrulae before the archenteron was formed, no significant difference in lectin-mediated agglutinability was observed, even after having been cultured in vitro in absence of inducing tissue. These results suggest that the target of the inducing signal generated in the mesoblast is likely to be located on the surface of epiblast cells. Additional experiments showed that cells pretreated with colchicine, cytochalasin B or colchicine and cytochalasin B simultaneously exhibit no significant variation in agglutinability, suggesting that the cytoskeleton was not be involved in the cell surface alteration here described. Treatment of whole embryos or sandwich explants with concanavalin A or phytohemagglutinin has no effect on neural tube formation, suggesting that the carbohydratecontaining binding sites for these lectins are not involved in primary embryonic induction. Changes in cell agglutinability described in this paper are to be interpreted thus as a secondary expression of structural alterations in the cell surface concomitant with neural determination.

Rapid qualitative changes in mRNA populations in cultured human lymphocytes: comparison of the effects of cycloheximide and concanavalin A

1984 ◽  
Vol 62 (9) ◽  
pp. 859-864 ◽  
Author(s):  
Donald R. Forsdyke
Keyword(s):  
Concanavalin A ◽  
Human Lymphocytes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Lymphocyte Activation ◽  
Relative Mass ◽  
Protein Synthesis Inhibitor ◽  
Synthesis Inhibitor ◽  
Mrna Species ◽  
Reticulocyte Lysate ◽  
Qualitative Changes

To examine the hypothesis that the stimulation of cultured lymphocytes by lectins involves the inactivation of a protein repressor of putative "activation genes," the effects of a protein synthesis inhibitor (cycloheximide) and a lectin (concanavalin A) were compared. Qualitative changes in mRNA populations were assessed by translating RNA prepared from cycloheximide- or lectin-treated cultures in a rabbit reticulocyte lysate. [35S]Methionine-labelled translation products were analysed by two-dimensional polyacrylamide gel electrophoresis. Cycloheximide increased the radioactive labelling of cultured lymphocytes with the RNA precursor [3H]uridine, as previously reported. This was observed during the first 3 h of culture; thereafter, cycloheximide was inhibitory. The period of increased labelling with [3H]uridine coincided with a period of great increase in mRNA corresponding to an acidic protein of a relative mass of approximately 55 000. This mRNA was not detected in RNA prepared from control cultures, but was one of the most abundant mRNA species detected in RNA prepared from cycloheximide-treated cultures. Increases in certain less abundant mRNA species were also noted. However, the mRNAs were not observed in RNA prepared from lectin-treated cultures. If an increase in these mRNAs is important for lymphocyte activation, then the increase must be to an extent not detected by our current methods.

Activation of deoxycytidine kinase during inhibition of DNA synthesis by 2-chloro-2′-deoxyadenosine (cladribine) in human lymphocytes

1998 ◽  
Vol 56 (9) ◽  
pp. 1175-1179 ◽  
Author(s):  
Mária Sasvári-Székely ◽  
Tatjana Spasokoukotskaja ◽  
Melinda Szóke ◽  
Zsolt Csapó ◽  
Ágnes Turi ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Human Lymphocytes ◽  
Deoxycytidine Kinase ◽  
Inhibition Of Dna Synthesis
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