The Experts below are selected from a list of 1765092 Experts worldwide ranked by ideXlab platform
Jonathan S Bromberg - One of the best experts on this subject based on the ideXlab platform.
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anti CD2 monoclonal antibody induced receptor changes ii interaction of CD2 and cd3
Cellular Immunology, 1996Co-Authors: Kenneth D Chavin, Yaozhong Ding, Jonathan S BrombergAbstract:Abstract Anti-CD3 monoclonal antibodies (mAbs) and anti-CD2 mAbs each prolong allograft survival and cause transient downmodulation of homologous receptor expression. Anti-CD2 mAbs also act synergistically with anti-CD3 mAbs to prolong allograft survival and induce tolerance. The effect of combined anti-CD2 and anti-CD3 mAb treatment on receptor expression was further analyzed with an in vitro model. The anti-CD2 mAb 12-15 caused CD2 expression on purified splenic T cells to decrease from 72.6% [mean channel fluorescence (MCF) 0.68] to 41.5% (0.45) total positive cells while CD3 expression remained unchanged [69.1% (3.47) to 76.4% (4.04)]. The anti-CD3 mAb 2C11 caused CD2 expression to increase from 72.6% (0.68) to 93.0% (1.74) while CD3 expression decreased from 69.1% (3.47) to 62.6% (2.15). The combination of anti-CD2 plus anti-CD3 preserved CD2 expression (72.6 to 71.1%) while still decreasing CD3 expression [69.1% (3.47) to 69.9% (2.37)]. Modulation of CD2 and CD3 expression was similar on mixed splenic T lymphocytes and isolated CD4 and CD8 subsets. Modulation did not change with the addition of the cytokines IL-1, IL-2, IL-4, IL-6, IL-10, TNFα, or TGFβ. Kinetic studies showed that modulation of CD2 was rapid, persistent, and of the same magnitude from Day 1 to Day 7 of culture while CD3 downmodulation was transient. The results of transcriptional analysis and receptor distribution suggested that downmodulation was due to receptor internalization while upmodulation was due to increased transcription. Analysis of expression of other adhesion molecules demonstrated that CD11a, CD18, CD44, CD45, CD48, CD54, and CD62L were significantly increased by either anti-CD2 or anti-CD3 mAbs while the combination was not synergistic. However, anti-CD3 significantly decreased VLA-4α (CD49d) expression and anti-CD2 enhanced this decrease. Conversely anti-CD3 significantly increased IL-2R (CD25) expression and anti-CD2 profoundly inhibited the increase. These results show that anti-CD2 and anti-CD3 mAbs significantly modulate CD2 and CD3 expression on T cells and modulation is accompanied by changes in the array of other T cell surface receptors. Changes in cell surface receptor display may provide an additional explanation for the synergistic effect of anti-CD2 plus anti-CD3 in prolonging allograft survival.
Martin-pierre Sauviat - One of the best experts on this subject based on the ideXlab platform.
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Characterization of the palytoxin-induced sodium conductance in frog skeletal muscle.
British Journal of Pharmacology, 1991Co-Authors: Eudes Ecault, Martin-pierre SauviatAbstract:1. The effects of palytoxin (PTX) on transmembrane potentials and currents of frog skeletal muscle were analyzed by intracellular microelectrode techniques and the double sucrose-gap voltage clamp method. 2. PTX irreversibly depolarized the membrane. The depolarization was Na-sensitive. 3. Under voltage clamp, PTX induced an inward resting current which did not inactivate, was inhibited by external Na+ removal and was a function of external Na concentration. 4. This resting current could be carried either by Na+, Li+, K+ or by guanidinium according to the permeability sequence K+ less than Li+ less than Na+ less than Gua+. 5. The PTX-induced current was only weakly sensitive to tetrodotoxin. It was reversibly and dose-dependently inhibited by amiloride with a one to one stoichiometry and a KD of 0.3 mM. 6. Acidic pH partially inhibited the current induced by PTX which was also highly sensitive to external CD2+ and La3+. The inhibitory sequence for divalent cations was: Mg2+ less than Ca2+ = Ba2+ = Mn2+ less than CD2+; with La3+ greater than CD2+. 7. The amplitude of the PTX-induced I(rest) was markedly reduced in the absence of external Ca2+. 8. PTX induced a Na+ resting conductance in frog skeletal muscle. The size of the channel induced by PTX is larger than the guanidinium ion. External membrane Ca2+ might be a cofactor involved in the mode of action of PTX.
Takashi Sakurai - One of the best experts on this subject based on the ideXlab platform.
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reversible effect of calcium binding protein regucalcin on the ca 2 induced inhibition of deoxyuridine 5 triphosphatase activity in rat liver cytosol
Molecular and Cellular Biochemistry, 1992Co-Authors: Masayoshi Yamaguchi, Takashi SakuraiAbstract:The effect of regucalcin, a calcium-binding protein isolated from rat liver cytosol, on deoxyuridine 5′-triphosphatase (dUTPase) in the cytosol of rat liver was investigated. Addition of Ca2+ up to 5.0 µM to the enzyme reaction mixture caused a significant decrease of dUTPase activity, while Zn2+, CD2+, Co2+, Al3+, Mn2+ and Ni2+ (10 µM) did not have an appreciable effect. The Ca2+-induced decrease of dUTPase activity was reversed by the presence of regucalcin; the effect was complete at 1.0 µM of the protein. Regucalcin had no effect on the basal activity of the enzyme. Meanwhile, the reversible effect of regucalcin on the Ca2+ (10 µM)-induced decrease of dUTPase activity was not altered by the coexistence of CD2+ or Zn2+ (10 µM). The present data suggest that liver cytosolic dUTPase is uniquely regulated by Ca2+ of various metals, and that the Ca2+ effect is reversed by regucalcin.
Sheng Luan - One of the best experts on this subject based on the ideXlab platform.
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cadmium impairs ion homeostasis by altering k and ca2 channel activities in rice root hair cells
Plant Cell and Environment, 2012Co-Authors: Minjie Zhu, Fugeng Zhao, Sheng LuanAbstract:Cadmium (CD2+) interferes with the uptake, transport and utilization of several macro- and micronutrients, which accounts, at least in part, for CD2+ toxicity in plants. However, the mechanisms underlying CD2+ interference of ionic homeostasis is not understood. Using biophysical techniques including membrane potential measurements, scanning ion-selective electrode technique for non-invasive ion flux assays and patch clamp, we monitored the effect of CD2+ on calcium (Ca2+) and potassium (K+) transport in root hair cells of rice. Our results showed that K+ and Ca2+ contents in both roots and shoots were significantly reduced when treated with exogenous CD2+. Further studies revealed that three cellular processes may be affected by CD2+, leading to changes in ionic homeostasis. First, CD2+ -induced depolarization of the membrane potential was observed in root hair cells, attenuating the driving force for cation uptake. Second, the inward conductance of Ca2+ and K+ was partially blocked by CD2+, decreasing uptake of K+ and Ca2+ . Third, the outward K+ conductance was CD2+ -inducible, decreasing the net content of K+ in roots. These results provide direct evidence that CD2+ impairs uptake of Ca2+ and K+, thereby disturbing ion homeostasis in plants.
Kenneth D Chavin - One of the best experts on this subject based on the ideXlab platform.
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anti CD2 monoclonal antibody induced receptor changes ii interaction of CD2 and cd3
Cellular Immunology, 1996Co-Authors: Kenneth D Chavin, Yaozhong Ding, Jonathan S BrombergAbstract:Abstract Anti-CD3 monoclonal antibodies (mAbs) and anti-CD2 mAbs each prolong allograft survival and cause transient downmodulation of homologous receptor expression. Anti-CD2 mAbs also act synergistically with anti-CD3 mAbs to prolong allograft survival and induce tolerance. The effect of combined anti-CD2 and anti-CD3 mAb treatment on receptor expression was further analyzed with an in vitro model. The anti-CD2 mAb 12-15 caused CD2 expression on purified splenic T cells to decrease from 72.6% [mean channel fluorescence (MCF) 0.68] to 41.5% (0.45) total positive cells while CD3 expression remained unchanged [69.1% (3.47) to 76.4% (4.04)]. The anti-CD3 mAb 2C11 caused CD2 expression to increase from 72.6% (0.68) to 93.0% (1.74) while CD3 expression decreased from 69.1% (3.47) to 62.6% (2.15). The combination of anti-CD2 plus anti-CD3 preserved CD2 expression (72.6 to 71.1%) while still decreasing CD3 expression [69.1% (3.47) to 69.9% (2.37)]. Modulation of CD2 and CD3 expression was similar on mixed splenic T lymphocytes and isolated CD4 and CD8 subsets. Modulation did not change with the addition of the cytokines IL-1, IL-2, IL-4, IL-6, IL-10, TNFα, or TGFβ. Kinetic studies showed that modulation of CD2 was rapid, persistent, and of the same magnitude from Day 1 to Day 7 of culture while CD3 downmodulation was transient. The results of transcriptional analysis and receptor distribution suggested that downmodulation was due to receptor internalization while upmodulation was due to increased transcription. Analysis of expression of other adhesion molecules demonstrated that CD11a, CD18, CD44, CD45, CD48, CD54, and CD62L were significantly increased by either anti-CD2 or anti-CD3 mAbs while the combination was not synergistic. However, anti-CD3 significantly decreased VLA-4α (CD49d) expression and anti-CD2 enhanced this decrease. Conversely anti-CD3 significantly increased IL-2R (CD25) expression and anti-CD2 profoundly inhibited the increase. These results show that anti-CD2 and anti-CD3 mAbs significantly modulate CD2 and CD3 expression on T cells and modulation is accompanied by changes in the array of other T cell surface receptors. Changes in cell surface receptor display may provide an additional explanation for the synergistic effect of anti-CD2 plus anti-CD3 in prolonging allograft survival.