scholarly journals Selective inhibition of the growth of human erythroid bursts by monoclonal antibodies against transferrin or the transferrin receptor

Blood ◽  
1986 ◽  
Vol 67 (6) ◽  
pp. 1631-1638 ◽  
Author(s):  
KM Shannon ◽  
JW Larrick ◽  
SA Fulcher ◽  
KB Burck ◽  
J Pacely ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Transferrin Receptor ◽  
Thymidine Incorporation ◽  
Selective Inhibition ◽  
Receptor Expression ◽  
Cell Surface Receptor ◽  
Transferrin Receptors ◽  
Human Erythropoietin ◽  
Surface Receptor ◽  
Transferrin Receptor Expression

Abstract The relative requirements of colonies derived from erythroid (BFU-E) and myeloid (CFU-c) progenitors for transferrin were examined using monoclonal antibodies directed against the transferrin molecule (TF-6) or its cell surface receptor (TFR-A12, TFR1–2B). Growth of erythroid bursts was profoundly reduced at concentrations of all three antibodies that had no effect on CFU-c-derived colonies. When TFR1–2B was layered over cultures established one to seven days previously, further burst development was inhibited, and degeneration of early erythroid colonies was observed. Addition of erythropoietin augmented transferrin receptor expression on cells harvested after 1 to 2 weeks in culture and analyzed by flow cytometry. Recombinant human erythropoietin gave results comparable to those obtained in experiments using human urinary erythropoietin. Analysis of erythroblasts plucked directly from culture plates confirmed the presence of transferrin receptors on BFU-E-derived colonies. Thymidine incorporation was maximal early in the second week of culture and coincided with high transferrin receptor expression. These data demonstrate that transferrin must be available into the second week of culture to support the growth and differentiation of BFU- E-derived erythroid bursts, that the generation of erythroid colonies from BFU-E is more dependent on transferrin than myeloid colony formation from CFU-c, and that erythropoietin modulates the expression of transferrin receptors on growing bursts.

scholarly journals Selective inhibition of the growth of human erythroid bursts by monoclonal antibodies against transferrin or the transferrin receptor

Blood ◽  
1986 ◽  
Vol 67 (6) ◽  
pp. 1631-1638
Author(s):  
KM Shannon ◽  
JW Larrick ◽  
SA Fulcher ◽  
KB Burck ◽  
J Pacely ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Transferrin Receptor ◽  
Thymidine Incorporation ◽  
Selective Inhibition ◽  
Receptor Expression ◽  
Cell Surface Receptor ◽  
Transferrin Receptors ◽  
Human Erythropoietin ◽  
Surface Receptor ◽  
Transferrin Receptor Expression

The relative requirements of colonies derived from erythroid (BFU-E) and myeloid (CFU-c) progenitors for transferrin were examined using monoclonal antibodies directed against the transferrin molecule (TF-6) or its cell surface receptor (TFR-A12, TFR1–2B). Growth of erythroid bursts was profoundly reduced at concentrations of all three antibodies that had no effect on CFU-c-derived colonies. When TFR1–2B was layered over cultures established one to seven days previously, further burst development was inhibited, and degeneration of early erythroid colonies was observed. Addition of erythropoietin augmented transferrin receptor expression on cells harvested after 1 to 2 weeks in culture and analyzed by flow cytometry. Recombinant human erythropoietin gave results comparable to those obtained in experiments using human urinary erythropoietin. Analysis of erythroblasts plucked directly from culture plates confirmed the presence of transferrin receptors on BFU-E-derived colonies. Thymidine incorporation was maximal early in the second week of culture and coincided with high transferrin receptor expression. These data demonstrate that transferrin must be available into the second week of culture to support the growth and differentiation of BFU- E-derived erythroid bursts, that the generation of erythroid colonies from BFU-E is more dependent on transferrin than myeloid colony formation from CFU-c, and that erythropoietin modulates the expression of transferrin receptors on growing bursts.

Effect of iron on transferrin receptor expression by human placental syncytiotrophoblast cells

1997 ◽  
Vol 9 (6) ◽  
pp. 609 ◽  
Author(s):  
Martha L. Kennedy ◽  
Gordon C. Douglas ◽  
Barry F. King
Keyword(s):  
Transferrin Receptor ◽  
Iron Status ◽  
Primary Cultures ◽  
Receptor Expression ◽  
Transferrin Receptors ◽  
Iron Salts ◽  
Intracellular Receptor ◽  
Cytotrophoblast Cells ◽  
Diferric Transferrin ◽  
Transferrin Receptor Expression

Transferrin receptor expression has been examined in primary cultures of morphologically differentiated placental syncytiotrophoblast cells. More than 90% of the cells were multinucleated. Incubation of syncytiotrophoblast for 4 days in the presence of iron salts had no effect on receptor expression assessed by measuring the binding of 125I-labelled transferrin. However, incubation of cells in the presence of human diferric transferrin (10-100 µM) led to a 50% decrease in surface and intracellular receptor expression. This down-regulation was not accompanied by a signicant decrease in receptor synthesis. In contrast to syncytiotrophoblast, expression of intracellular transferrin receptors in non-differentiated cytotrophoblast cells decreased when cells were cultured with iron salts; this was accompanied by decreased receptor synthesis. Addition of diferric transferrin to cytotrophoblast cells led to a 50% reduction in surface and intracellular receptor expression, similar to that seen in the syncytiotrophoblast. This reduction was accompanied by a decrease in receptor synthesis. In contrast to that of most cell types, the expression and distribution of trophoblast transferrin receptors were not altered by insulin, epidermal growth factor or hydrocortisone. These characteristics of syncytiotrophoblast transferrin receptor expression may assist in ensuring a supply of iron to the fetus regardless of the maternal iron status.

Tumour Necrosis Factor-α Upregulates Transferrin Receptors in K 562 Cells

1994 ◽  
Vol 22 (3) ◽  
pp. 145-152 ◽  
Author(s):  
M Nezu ◽  
H Iwagaki ◽  
H Aoki ◽  
N Tanaka ◽  
K Orita
Keyword(s):  
Tumour Necrosis Factor ◽  
Transferrin Receptor ◽  
Tumour Necrosis ◽  
Receptor Expression ◽  
Transferrin Receptors ◽  
Tumour Necrosis Factor Α ◽  
K 562 Cells ◽  
Factor Α ◽  
Transferrin Receptor Expression ◽  
Necrosis Factor

The effects of tumour necrosis factor-α on transferrin receptor expression in a human chronic myelocytic leukaemia cell line, K 562 cells, were studied. Cytofluorometry studies showed that the numbers of transferrin receptors in exponentially growing K 562 cells were increased when the cells were incubated with tumour necrosis factor-α for 24 h. The induction of transferrin receptors by tumour necrosis factor-α may be mediated by a mechanism that is independent of growth since cell growth in treated cultures did not differ from that in the controls. The DNA contents of K 562 cells treated with tumour necrosis factor-α showed that after 24 h there were less cells in the G1 and S phases and more cells in the G2/M phase than in the control group. The phase of upregulation of transferrin receptors induced by tumour necrosis factor-α may be dependent on the cell cycle. This new evidence that tumour necrosis factor-α upregulates transferrin receptors suggests a cancer-anaemia cascade in which the cancer burden state activates macrophage release of tumour necrosis factor-α as a result of transferrin receptor expression.

scholarly journals Effect of aluminium on iron uptake and transferrin-receptor expression by human erythroleukaemia K562 cells

1990 ◽  
Vol 272 (2) ◽  
pp. 377-382 ◽  
Author(s):  
S J McGregor ◽  
M L Naves ◽  
R Oria ◽  
J K Vass ◽  
J H Brock
Keyword(s):  
Transferrin Receptor ◽  
Iron Uptake ◽  
K562 Cells ◽  
Inhibitory Effect ◽  
Receptor Expression ◽  
Transferrin Receptors ◽  
High Concentration ◽  
Intracellular Release ◽  
Aluminium Citrate ◽  
Transferrin Receptor Expression

Incubation of human erythroleukaemia K562 cells with Al-transferrin inhibited iron uptake from 59Fe-transferrin by about 80%. The inhibition was greater than that produced by a similar quantity of Fe-transferrin. Preincubation of cells for 6 h with either Al-transferrin or Fe-transferrin diminished the number of surface transferrin receptors by about 40% compared with cells preincubated with apo-transferrin. Al-transferrin did not compete significantly with Fe-transferrin for transferrin receptors and, when cells were preincubated for 15 min instead of 6 h, the inhibitory effect of Al-transferrin on receptor expression was lost. Both forms of transferrin also decreased the level of transferrin receptor mRNA by about 50%, suggesting a common regulatory mechanism. Aluminium citrate had no effect on iron uptake or transferrin-receptor expression. AlCl3 also had no effect on transferrin-receptor expression, but at high concentration it caused an increase in iron uptake by an unknown, possibly non-specific, mechanism. Neither Al-transferrin nor AlCl3 caused a significant change in cell proliferation. It is proposed that aluminium, when bound to transferrin, inhibits iron uptake partly by down-regulating transferrin-receptor expression and partly by interfering with intracellular release of iron from transferrin.

Diltiazem inhibits transferrin receptor expression and causes G1 arrest in normal and neoplastic T cells

1986 ◽  
Vol 6 (12) ◽  
pp. 4244-4250
Author(s):  
L M Neckers ◽  
S Bauer ◽  
R C McGlennen ◽  
J B Trepel ◽  
K Rao ◽  
...  
Keyword(s):  
T Cells ◽  
Transferrin Receptor ◽  
Interleukin 2 ◽  
Receptor Expression ◽  
Calcium Flux ◽  
G1 Arrest ◽  
Receptor Mrna ◽  
Interleukin 2 Receptor ◽  
Transferrin Receptor Expression ◽  
Malignant T Cells

Transferrin receptor expression is essential for the proliferation of both normal and malignant T cells. While transferrin receptor expression in normal T cells is tightly coupled to interleukin-2 receptor expression, transferrin receptor expression in malignant cells is usually constitutive and is released from this constraint. Temporally, the appearance of these membrane receptors is preceded by changes in the expression of the proto-oncogenes c-myc and c-myb. In addition, although an increase in the level of intracellular free calcium occurs early in the sequence of T-cell activation, the activation events dependent on this calcium flux have not been resolved. In the present study we report that diltiazem, an ion channel-blocking agent that inhibits calcium influx, arrested the growth in vitro of both normal and malignant human T cells in the G1 phase of the cell cycle. However, diltiazem did not inhibit the expression of c-myc or interleukin-2 receptor mRNA and protein in normal mitogen-activated T cells or the constitutive expression of c-myc and c-myb mRNA in malignant T cells (T acute lymphoblastic leukemia cells). In contrast, diltiazem prevented the induction of transferrin receptor (mRNA and protein) in normal T cells and caused a progressive loss of transferrin receptor (mRNA and protein) in malignant T cells. These data demonstrate that diltiazem can dissociate several growth-related processes normally occurring in G1 and thereby disrupt the biochemical cascade leading to cell proliferation.

Decreased transferrin receptor expression by neuromelanin cells in restless legs syndrome

Neurology ◽  
2004 ◽  
Vol 62 (9) ◽  
pp. 1563-1567 ◽  
Author(s):  
J. R. Connor ◽  
X. S. Wang ◽  
S. M. Patton ◽  
S. L. Menzies ◽  
J. C. Troncoso ◽  
...  
Keyword(s):  
Restless Legs Syndrome ◽  
Transferrin Receptor ◽  
Receptor Expression ◽  
Restless Legs ◽  
Transferrin Receptor Expression
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