scholarly journals HUMORAL IMMUNOSTIMULATION

1974 ◽  
Vol 139 (2) ◽  
pp. 367-379 ◽  
Author(s):  
William T. Shearer ◽  
Gordon W. Philpott ◽  
Charles W. Parker
Keyword(s):  
Cell Growth ◽  
Cell Membrane ◽  
Cell Surface ◽  
Dna Synthesis ◽  
Gamma Globulin ◽  
Cell Membrane Transport ◽  
Nucleoside Uptake ◽  
Alter Cell Membrane ◽  
Stimulation Of ◽  
Intense Stimulation

Interaction of microgram quantities of highly purified rabbit anti-TNP antibodies with TNP-substituted HeLa, HEp-2, and L cells caused an intense stimulation of radioactive nucleoside ([125I]UdR and [3H]TdR) uptake which was maximal 24–72 h after exposure of cells to antibody. The stimulation of nucleoside uptake and presumaly DNA synthesis was shown to be immuno logically mediated because unsubstituted cells were not stimulated by anti-TNP antibody, normal rabbit gamma globulin did not stimulate TNP-cells, and a hapten inhibitor, ϵ-DNP-lysine, prevented the stimulation of TNP-cells by anti-TNP antibody. These findings demonstrate that interaction of antibody with cell surface antigen can alter cell membrane transport, and possibly can enhance cell growth.

Use of Isolated Tight Epithelia to Study the Site and Mode of Drug Action on Cell Membrane Transport: Effect of the Antipsychotic Agent Trifluoperazine

1990 ◽  
Vol 17 (3) ◽  
pp. 224-227
Author(s):  
Henning F. Bjerregaard
Keyword(s):  
Cell Membrane ◽  
Toxic Effect ◽  
Membrane Transport ◽  
Antipsychotic Agent ◽  
Na Transport ◽  
Tight Epithelia ◽  
Acute Toxic Effect ◽  
Cell Membrane Transport ◽  
Dose Dependent ◽  
Stimulation Of

The aim of the present study was to investigate the site and mode of trifluoperazine (TFP) action on cell membrane transport by the use of isolated frog skin. This cellular system gives access to the apical (outer) and basolateral (inner) membranes of the polarised epithelial cells. Both apical and basolateral TFP addition induced a dose-dependent stimulation of Na transport, and depolarised the cellular potential. The data indicate that TFP acts by increasing the Na permeability of the apical membrane. However, the mechanisms localised in the apical and basolateral membranes are quite different. Basolateral TFP addition increased Na transport due to a stimulation of PGE2 synthesis, whereas apical TFP addition abolished Na inhibition of the apical Na channels, and thereby enhanced the Na transport. An acute toxic effect on the electrophysiological parameters was noted after addition of high apical TFP concentrations (50–100μM). This toxic effect was dependent on the presence of Na in the apical solution.

Role of polyamines in glucocorticoid effects on pancreatic acinar AR42J cell growth and differentiation

1992 ◽  
Vol 262 (2) ◽  
pp. G285-G290
Author(s):  
C. D. Logsdon ◽  
F. Alves ◽  
S. Rosewicz
Keyword(s):  
Cell Growth ◽  
Dna Synthesis ◽  
Mrna Levels ◽  
Ar42j Cells ◽  
Glucocorticoid Induction ◽  
Cell Growth And Differentiation ◽  
Ar42j Cell ◽  
Inhibition Of Dna Synthesis ◽  
Stimulation Of

We previously found that glucocorticoids inhibit growth and increase differentiation in rat pancreatic acinar AR42J cells. In the current study, we examined the role of polyamines in these effects. Treatment of AR42J cells with the ornithine decarboxylase (ODC) inhibitor difluoromethylornithine (DFMO) inhibited DNA synthesis. Thus polyamines are required for AR42J cell growth. However, we have previously shown that dexamethasone (Dex) increased AR42J cell ODC activity and mRNA levels. In the current study, we found that Dex treatment increased cellular putrescine levels. These increases in ODC and putrescine occurred during Dex-induced inhibition of DNA synthesis. Therefore, in AR42J cells, ODC activity and polyamine levels are not strictly growth related. To examine the requirement for glucocorticoid induction of ODC activity in glucocorticoid stimulation of differentiation, we examined the effects of DFMO on amylase gene expression and cholecystokinin binding. DFMO reduced cell amylase content while having little effect on mRNA levels in both Dex-treated and untreated cells. In contrast, DFMO had little effect on control CCK binding but inhibited the Dex-induced increase. Thus polyamines are necessary for growth and glucocorticoid-induced differentiation of AR42J cells; however, effects of glucocorticoids on AR42J cell growth and differentiation are not mediated by effects on ODC.

Stimulation of cell growth and DNA synthesis by peripheral benzodiazepine

1990 ◽  
Vol 49 (2) ◽  
pp. 115-120 ◽  
Author(s):  
K. Ikezaki ◽  
K.L. Black
Keyword(s):  
Cell Growth ◽  
Dna Synthesis ◽  
Stimulation Of

Polyamine-modulated expression of c-myc plays a critical role in stimulation of normal intestinal epithelial cell proliferation

2005 ◽  
Vol 288 (1) ◽  
pp. C89-C99 ◽  
Author(s):  
Lan Liu ◽  
Li Li ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Huifang M. Zhang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Epithelial Cell ◽  
Dna Synthesis ◽  
Intestinal Epithelial Cell ◽  
Small Intestinal Mucosa ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation ◽  
Myc Gene ◽  
Stimulation Of

The nuclear protein c-Myc is a transcription factor involved in the control of cell cycle. Our previous studies indicated that cellular polyamines are absolutely required for cell proliferation in crypts of small intestinal mucosa and that polyamines have the ability to stimulate expression of the c- myc gene. The current study went further to determine whether induced nuclear c-Myc plays a role in stimulation of cell proliferation by polyamines in intestinal crypt cells (IEC-6 line). Exposure of normal quiescent cells after 24-h serum deprivation to 5% dialyzed fetal bovine serum (dFBS) increased both cellular polyamines and expression of the c- myc gene. Increased c-Myc protein formed heterodimers with its binding partner, Max, and specifically bound to the Myc/Max binding site, which was associated with an increase in DNA synthesis. Depletion of cellular polyamines by pretreatment with α-difluoromethylornithine (DFMO) prevented increases in c- myc expression and DNA synthesis induced by 5% dFBS. c- Myc gene transcription and cell proliferation decreased in polyamine-deficient cells, whereas the natural polyamine spermidine given together with DFMO maintained c- myc gene expression and cell growth at normal levels. Disruption of c- myc expression using specific c- myc antisense oligomers not only inhibited normal cell growth (without DFMO) but also prevented the restoration of cell proliferation by spermidine in polyamine-deficient cells. Ectopic expression of wild-type c- myc by recombinant adenoviral vector containing c- myc cDNA increased cell growth. These results indicate that polyamine-induced nuclear c-Myc interacts with Max, binds to the specific DNA sequence, and plays an important role in stimulation of normal intestinal epithelial cell proliferation.

Effects of colchicine and vinblastine on the phytohaemagglutinin-induced transformation of lymphocytes

1977 ◽  
Vol 27 (1) ◽  
pp. 183-198
Author(s):  
J. Thyberg ◽  
S. Moskalewski ◽  
U. Friberg
Keyword(s):  
Cell Growth ◽  
Dna Synthesis ◽  
Golgi Complex ◽  
Human Lymphocytes ◽  
Blast Transformation ◽  
Drug Induced ◽  
Mitogenic Stimulation ◽  
Cytoplasmic Microtubules ◽  
Pha Stimulation ◽  
Stimulation Of

The effects of 2 microtubular-disruptive drugs, colchicine and vinblastine, on the phytohaemagglutinin (PHA)-induced blast transformation and mitogenic stimulation of human lymphocytes were studied. Both drugs markedly inhibited cell growth and DNA synthesis and lowered the mitotic index. No microtubules were seen with the electron microscope in cells treated with PHA plus colchicine or vinblastine. Moreover, the PHA-induced development of all organelles was partially inhibited by these drugs, especially that of the Golgi complex. As compared to cells treated with PHA alone, the dictyosomes were fewer, not so clearly localized in one area of the cytoplasm, and contained a decreased number of cisternae and an increased number of vacuoles. These results indicate that cytoplasmic microtubules play an important role in the PHA-induced blast transformation and mitogenic stimulation of lymphocytes. It is suggested that the microtubules function in the structural organization of the cell and particularly the Golgi complex. In the drug-induced absence of microtubules this and other organelle systems do not respond as usual to PHA stimulation, which could largely explain the decreased cell growth. This in turn suggests that lowered mitotic activity is a result of inhibition of cell growth, as a critical amount of G1-associated cell growth is believed to be required for the initiation of DNA synthesis and thus mitosis.

Ferritin-Conjugated Antibody for the Demonstration of Isoantigens on the Surface of Murine Cells

1968 ◽  
Vol 26 ◽  
pp. 48-49
Author(s):  
T. Aoki ◽  
J. Izard ◽  
U. Hämmerling ◽  
E. de Harven ◽  
L. J. Old
Keyword(s):  
Cell Surface ◽  
Gamma Globulin ◽  
Leukemia Cells ◽  
Labelling Technique ◽  
Direct Labelling ◽  
Labelling Method

Although a variety of viral and cellular antigens have been demonstrated by ferritin-labeled antibody, this technique has not been used to locate isoantigens on the surface of nucleated cells. The recognition of several systems of isoantigens on the surface of thymocytes, lymphocytes and leukemia cells of the mouse and the ease with which these cells can be obtained in free suspension led us to consider the ferritin-labelling method to determine the amount and location of these isoantigens on the cell surface. Because of the problems involved in the direct labelling of mouse gamma globulin by ferritin, we have chosen an indirect labelling technique (i.e. ferritin-conjugated rabbit anti mouse γG)to detect localization of mouse isoantibody.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

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