scholarly journals SIALIC ACIDS ON THE PLASMA MEMBRANE OF CULTURED HUMAN LYMPHOID CELLS

1972 ◽  
Vol 53 (2) ◽  
pp. 466-473 ◽  
Author(s):  
Steven A. Rosenberg ◽  
Albert B. Einstein
Keyword(s):  
Cell Cycle ◽  
Sialic Acid ◽  
Sialic Acids ◽  
Lymphoid Cells ◽  
Limited Time ◽  
Total Sialic Acid ◽  
Human Lymphoid Cell ◽  
G2 Phase ◽  
Lymphoid Cell Lines ◽  
Synchronized Cultures

From 61 to 92% of the total sialic acid of a variety of human lymphoid cell lines maintained in tissue culture is present on the cell surface as measured by its susceptibility to cleavage by Clostridium perfringens neuraminidase. These cells contain from 1.22 x 108 to 6.99 x 108 molecules of surface sialic acid per cell. In synchronized cultures synthesis of surface sialic acid occurs only during a limited time in the late G2 phase of the cell cycle. The amount and density of surface sialic acid vary considerably throughout the cell cycle.

scholarly journals Effect of cell cycle position on dexamethasone binding by mouse and human lymphoid cell lines: correlation between an increase in dexamethasone binding during S phase and dexamethasone sensitivity

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 105-113
Author(s):  
CW Distelhorst ◽  
BM Benutto ◽  
RA Bergamini
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Lymphoid Cell ◽  
S Phase ◽  
Lymphoid Cells ◽  
Cell Protein ◽  
G1 Phase ◽  
Cycle Phase ◽  
Human Lymphoid Cell ◽  
Lymphoid Cell Lines

We determined the effect of cell cycle position on the amount of dexamethasone that was specifically bound by mouse and human lymphoid cell lines. Cell lines that were either sensitive or resistant to growth inhibition by dexamethasone were compared. Exponentially growing cells were separated by centrifugal elutriation into fractions that corresponded to different positions in the cell cycle. The cell cycle phase distribution of each fraction was estimated by flow cytometry and autoradiography. The amount of dexamethasone bound per cell in each fraction was measured by a whole cell binding assay. In three dexamethasone-sensitive cell lines (two mouse and one human), we found that the amount of dexamethasone bound per cell increased 2–4-fold between G1 phase and S phase, and then decreased during G2/M phase. Results were the same when the amount of dexamethasone bound per milligram of cell protein was measured. Binding affinity was the same during G1 phase and S phase, but the proportion of bound dexamethasone that translocated to the nucleus was greater during S phase. In contrast, we found that the amount of dexamethasone bound per cell by three dexamethasone-resistant cell lines (two mouse and one human) did not increase during S phase. Our results indicate that cell cycle changes in dexamethasone binding are not simply related to changes in cell protein or cell volume during the cell cycle. An increase in dexamethasone binding during S phase may be required for dexamethasone to inhibit cell growth, and a failure of dexamethasone binding to increase during S phase might represent a new mechanism of dexamethasone resistance in lymphoid cells.

scholarly journals Effect of cell cycle position on dexamethasone binding by mouse and human lymphoid cell lines: correlation between an increase in dexamethasone binding during S phase and dexamethasone sensitivity

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 105-113 ◽  
Author(s):  
CW Distelhorst ◽  
BM Benutto ◽  
RA Bergamini
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Lymphoid Cell ◽  
S Phase ◽  
Lymphoid Cells ◽  
Cell Protein ◽  
G1 Phase ◽  
Cycle Phase ◽  
Human Lymphoid Cell ◽  
Lymphoid Cell Lines

Abstract We determined the effect of cell cycle position on the amount of dexamethasone that was specifically bound by mouse and human lymphoid cell lines. Cell lines that were either sensitive or resistant to growth inhibition by dexamethasone were compared. Exponentially growing cells were separated by centrifugal elutriation into fractions that corresponded to different positions in the cell cycle. The cell cycle phase distribution of each fraction was estimated by flow cytometry and autoradiography. The amount of dexamethasone bound per cell in each fraction was measured by a whole cell binding assay. In three dexamethasone-sensitive cell lines (two mouse and one human), we found that the amount of dexamethasone bound per cell increased 2–4-fold between G1 phase and S phase, and then decreased during G2/M phase. Results were the same when the amount of dexamethasone bound per milligram of cell protein was measured. Binding affinity was the same during G1 phase and S phase, but the proportion of bound dexamethasone that translocated to the nucleus was greater during S phase. In contrast, we found that the amount of dexamethasone bound per cell by three dexamethasone-resistant cell lines (two mouse and one human) did not increase during S phase. Our results indicate that cell cycle changes in dexamethasone binding are not simply related to changes in cell protein or cell volume during the cell cycle. An increase in dexamethasone binding during S phase may be required for dexamethasone to inhibit cell growth, and a failure of dexamethasone binding to increase during S phase might represent a new mechanism of dexamethasone resistance in lymphoid cells.

scholarly journals Cytotoxicity of farnesyltransferase inhibitors in lymphoid cells mediated by MAPK pathway inhibition and Bim up-regulation

Blood ◽  
2011 ◽  
Vol 118 (18) ◽  
pp. 4872-4881 ◽  
Author(s):  
Husheng Ding ◽  
Jennifer Hackbarth ◽  
Paula A. Schneider ◽  
Kevin L. Peterson ◽  
X. Wei Meng ◽  
...  
Keyword(s):  
Cell Lines ◽  
Lymphoid Cell ◽  
Mapk Pathway ◽  
Lymphoid Cells ◽  
Farnesyltransferase Inhibitors ◽  
Death Domain ◽  
Nucleotide Exchange ◽  
Human Lymphoid Cell ◽  
Induced Apoptosis ◽  
Lymphoid Cell Lines

Abstract The mechanism of cytotoxicity of farnesyltransferase inhibitors is incompletely understood and seems to vary depending on the cell type. To identify potential determinants of sensitivity or resistance for study in the accompanying clinical trial (Witzig et al, page 4882), we examined the mechanism of cytotoxicity of tipifarnib in human lymphoid cell lines. Based on initial experiments showing that Jurkat variants lacking Fas-associated death domain or procaspase-8 undergo tipifarnib-induced apoptosis, whereas cells lacking caspase-9 or overexpressing Bcl-2 do not, we examined changes in Bcl-2 family members. Tipifarnib caused dose-dependent up-regulation of Bim in lymphoid cell lines (Jurkat, Molt3, H9, DoHH2, and RL) that undergo tipifarnib-induced apoptosis but not in lines (SKW6.4 and Hs445) that resist tipifarnib-induced apoptosis. Further analysis demonstrated that increased Bim levels reflect inhibition of signaling from c-Raf to MEK1/2 and ERK1/2. Additional experiments showed that down-regulation of the Ras guanine nucleotide exchange factor RasGRP1 diminished tipifarnib sensitivity, suggesting that H-Ras or N-Ras is a critical farnesylation target upstream of c-Raf in lymphoid cells. These results not only trace a pathway through c-Raf to Bim that contributes to tipifarnib cytotoxicity in human lymphoid cells but also identify potential determinants of sensitivity to this agent.

scholarly journals THE RELATIONSHIP BETWEEN ß2-MICROGLOBULIN AND IMMUNOGLOBULIN IN CULTURED HUMAN LYMPHOID CELL LINES

1973 ◽  
Vol 137 (3) ◽  
pp. 838-843 ◽  
Author(s):  
T. H. Hütteroth ◽  
H. Cleve ◽  
S. D. Litwin ◽  
M. D. Poulik
Keyword(s):  
Cell Surface ◽  
Cell Lines ◽  
Specific Antibody ◽  
Lymphoid Cell ◽  
Lymphoid Cells ◽  
Human Lymphoid Cell ◽  
Membrane Antigens ◽  
The Relationship ◽  
Lymphoid Cell Lines

ß2-microglobulin was detected on the cell surface and in the medium of human lymphoid cells established in long-term culture. The secretion of ß2-microglobulin was relatively uniform when different cell lines were compared, whereas IgG production varied widely. κ- and µ-membrane antigens were modulated by specific antibody; ß2-microglobulin was not modulated. Anti-κ and anti-µ antisera had no effect on the expression of membrane ß2-microglobulin, nor had anti-ß2-microglobulin antiserum any effect on the expression of κ- and µ-membrane antigens.

scholarly journals BIPHASIC EFFECT OF ADENOSINE ON CELL GROWTH AND CELL CYCLE OF HUMAN LYMPHOID CELL LINES: 219

1985 ◽  
Vol 19 (7) ◽  
pp. 780-780
Author(s):  
Peter M Van Der Kraan ◽  
Peter M Van Zandvoort ◽  
Ronney A De Abreu ◽  
Jan A J M Bakkeren ◽  
Jan P R M Van Laarhoven ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Cell Lines ◽  
Lymphoid Cell ◽  
Human Lymphoid Cell ◽  
Biphasic Effect ◽  
Lymphoid Cell Lines

scholarly journals SEPARATION OF HUMAN LYMPHOID CELLS INTO G1, S, AND G2 CELL CYCLE POPULATIONS BY USE OF A VELOCITY SEDIMENTATION TECHNIQUE

1973 ◽  
Vol 137 (2) ◽  
pp. 343-358 ◽  
Author(s):  
Lloyd K. Everson ◽  
Donald N. Buell ◽  
G. Nicholas Rogentine
Keyword(s):  
Cell Cycle ◽  
Surface Membrane ◽  
Fold Increase ◽  
Growth Patterns ◽  
Cell Cycle Phase ◽  
Lymphoid Cells ◽  
Velocity Sedimentation ◽  
Cycle Phase ◽  
Growth Media ◽  
Human Lymphoid Cell

Human lymphoid tissue culture cells can be separated according to cell size and corresponding cell cycle phase with a velocity sedimentation centrifugation method employing a continuous 5–20% wt/wt Ficoll gradient. A 7-fold increase in streaming limit was achieved by placing a buffer zone of isosmolar 5% Ficoll on top of the gradient before application of the cell load. The various pooled populations of cells from upper, middle, and lower areas of the gradient were characterized using autoradiographic, TCA-precipitable 3H]thymidine incorporation, and Fuelgen microspectrophotometric methods. The upper range of the gradient contains cells in the G1 cell cycle phase; the lower range, cells in the G2 phase; cells found in the middle of the gradient belong largely to the S phase of the cell cycle. These gradient-separated cell pools contained relatively little contamination with cells from other phases of the cell cycle and, when explanted from the gradient into fresh growth media, showed growth patterns characteristic of synchronized cell populations. This system of cell separation provides a useful tool for investigating the relationship of the cell cycle to surface membrane and metabolic characteristics in human lymphoid cell culture systems.

scholarly journals A revision of the Dictyostelium discoideum cell cycle

1984 ◽  
Vol 70 (1) ◽  
pp. 111-131 ◽  
Author(s):  
C.J. Weijer ◽  
G. Duschl ◽  
C.N. David
Keyword(s):  
Cell Cycle ◽  
Dictyostelium Discoideum ◽  
Nuclear Dna ◽  
Average Length ◽  
Dna Contents ◽  
Total Dna ◽  
G2 Phase ◽  
Almost All ◽  
Nuclear Dna Contents ◽  
Synchronized Cultures

We have investigated the Dictyostelium discoideum cell cycle using fluorometric determinations of cellular and nuclear DNA contents in exponentially growing cultures and in synchronized cultures. Almost all cells are in G2 during both growth and development. There is no G1 period, S phase is less than 0.5 h, and G2 has an average length of 6.5 h in axenically grown cells. Mitochondrial DNA, which constitutes about half of the total DNA, is replicated throughout the cell cycle. There is no difference in the nuclear DNA contents of axenically grown and bacterially grown cells. Thus the long cell cycle in axenically grown cells is due to a lengthening of the G2 phase.

scholarly journals Expression of HOXC4, HOXC5, and HOXC6 in human lymphoid cell lines, leukemias, and benign and malignant lymphoid tissue

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 1737-1745 ◽  
Author(s):  
J Bijl ◽  
JW van Oostveen ◽  
M Kreike ◽  
E Rieger ◽  
LM van der Raaij-Helmer ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Lymphoid Cell ◽  
Lymphoid Cells ◽  
Normal Donor ◽  
Rt Pcr ◽  
Neoplastic Cells ◽  
Human Lymphoid Cell ◽  
Hodgkin's Lymphomas ◽  
Lymphoid Cell Lines

Abstract Besides their regulatory role in embryogenesis, homeobox (HOX) genes are expressed in a specific manner in hematopoietic cell lineages, implying a role in the molecular regulation of hematopoiesis. Some HOX C cluster genes are found to be expressed in lymphoid cells of mice and humans. Their function and expression in normal hematopoiesis are still largely unknown. We have studied the mRNA expression of HOXC4, HOXC5, and HOXC6 in several stages of lymphocyte maturation by reverse transcriptase-polymerase chain reaction (RT-PCR) and RNA in situ hybridization (RISH). We examined CD34+/CD38low and CD34+/CD38high cells obtained from normal donor bone marrow (BM), a panel of 19 lymphoid cell lines, several types of leukemias and non-Hodgkin's lymphomas (NHL), and lymphocytes isolated from tonsillar tissue and peripheral blood (PB). HOXC4 and HOXC6 were found to be expressed during maturation in B- and T-lymphoid cells. The expression of each gene was found to be initiated at different cell maturation stages. HOXC4 transcripts were present in CD34+/CD38low cells, which are thought to comprise stem cells and noncommitted progenitor cells, and in subsequent stages to terminally maturated lymphoid cells. HOXC6 expression is initiated in equivalents of prothymocyte and pre-pre-B cell stage and remains present in mature cells. However, HOXC5 is only expressed in neoplastic cell lines and in neoplastic cells of NHL, but not in CD34+ BM cells, nor in resting or activated lymphoid cells isolated from tonsil, PB, or in leukemia cells. In cell lines, weak expression of HOXC5 is initiated in equivalents of pre-B cell and common thymocyte stage and is continuously expressed in mature cell lines. Semi-quantitative RT-PCR showed that expression levels of HOXC5 were much lower than those of HOXC4 and HOXC6; furthermore an increase of expression of HOXC4, HOXC5, and HOXC6 during lymphoid cell differentiation was demonstrated. Thus, mainly mature lymphoid cell lines and neoplastic cells of NHL do express HOXC5, in contrast to the lack of expression in normal lymphoid cells and leukemias. These findings suggest involvement of HOXC5 in lymphomagenesis.

Sialoglycoproteins and sialic acids ofPlasmodium knowlesischizont-infected erythrocytes and normal rhesus monkey erythrocytes

Parasitology ◽  
1986 ◽  
Vol 92 (3) ◽  
pp. 527-543 ◽  
Author(s):  
R. J. Howard ◽  
G. Reuter ◽  
J. W. Barnwell ◽  
R. Schauer
Keyword(s):  
Sialic Acid ◽  
Rhesus Monkey ◽  
Acid Content ◽  
Sialic Acids ◽  
Galactose Oxidase ◽  
Parasite Development ◽  
Sialic Acid Content ◽  
Acetylneuraminic Acid ◽  
Total Sialic Acid ◽  
Significant Difference

SUMMARYThe effects of malaria infection on RBC sialic acids and sialoglycoproteins were studied with asexual blood-stage infections ofPlasmodium knowlesiin rhesus monkeys. Glycoprotein radio-isotope labelling methods were used to compare the sialoglycoproteins of normal RBC andP. knowlesischizont-infected RBC (SI-RBC). Tritiation of glycoproteins from SI-RBC with the standard sialidase + galactose oxidase/NaB3H4method or standard periodate/NaB3H4method was significantly decreased when compared to normal RBC. However, tritium uptake into glycoproteins was normal when SI-RBC were treated with 5-fold higher concentrations of both enzymes in the first labelling method, or with a 5-fold increase in the molar ratio of periodate to sialic acid in the second method. The mobility of tritiated host cell glycoproteins on SDS–polyacrylamide gels was identical for SI-RBC and normal RBC. New bands, possibly glycoproteins, of 230, 160, 90, 52, and 30 kDa were detected after labelling SI-RBC by the modified periodate/NaB3H4method. Sialic acid analysis of normal rhesus monkey RBC (62μg/1010RBC) revealed that 46% of the total sialic acid wasN-glycolylneuraminic acid, 33% wasN-acetyl-9-O-acetylneuraminic acid, and the remainderN-acetylneuraminic acid. SI-RBC collected either directly from infected monkeys or afterin vitroculture of ring-infected RBC in horse serum, had increased total sialic acid (126 or 115μg/1010RBC, respectively). The sialic acid content of infected RBC must increase during parasite development since RBC infected with ring-stageP. knowlesihad the same content as normal RBC. There was no significant difference in the ratio of the three sialic acids of SI-RBC and normal RBC. In contrast, the uninfected RBC from infected blood of different monkeys showed marked variation in sialic acid composition and generally had a lower sialic acid content than normal RBC.

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