Warner J A, MacGlashan D W
Division of Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, MD 21239.
J Immunol. 1989 Mar 1;142(5):1669-77.
We have examined the changes in protein kinase C (PKC) which follow IgE-mediated activation of basophils. Exposure to 0.1 microgram/ml anti-IgE resulted in an increase in total cellular PKC (169 +/- 23% of control, histamine release (HR) = 33 +/- 7%, n = 12) which could be accounted for solely by the increase in membrane-associated PKC. These changes reached a maximum (280 +/- 48%) 1.0 min after challenge and declined to 190 +/- 38% after 5.0 min though histamine release was not complete until 5 to 10 min later. We found a good correlation between the increase in membrane-associated PKC and the eventual release of histamine (rs = 0.902). Donors whose basophils released less than 5% total histamine (n = 3, HR = 3 +/- 1%) showed a partial activation of PKC (173 +/- 18%) though much less than the remaining donors (increase in PKC = 346 +/- 59%, n = 9, HR = 43 +/- 7%). We observed no redistribution of cytosolic PKC at any time following exposure to anti-IgE. In contrast, 0.1 microgram/ml 2-O-tetradecanoyl-phorbol-13-acetate (HR = 36 +/- 3%, n = 3) promoted an increase in total cellular PKC, the loss of 31 +/- 4% of the cytosolic PKC and an 816 +/- 183% increase in membrane-associated PKC. Activation of PKC by anti-IgE was only partially dependent on extracellular calcium. In the absence of calcium, the increase in PKC was approximately 65% (n = 4) of that noted in the presence of 1mM calcium but these levels were sustained over much longer periods, failing to return to base line after 30 min. Higher than normal concentrations of calcium (5 to 10 mM) promoted rapid increases in PKC activity and accelerated the return to base line (back to prechallenge levels by 5 min). Suboptimal concentrations of anti-IgE (0.01 microgram/ml) attenuated the changes in membrane associated PKC and altered the kinetics of the response. The time required to reach maximum activity increased from 1.0 to 5.0 min with a corresponding decrease in the rate at which histamine was released. Higher concentrations of anti-IgE (1.0 microgram/ml) promoted a rapid increase in PKC (maximum increase in PKC = 501 +/- 59%, time = 0.5 min, HR = 28 +/- 2%) followed by an equally rapid return to base line levels.(ABSTRACT TRUNCATED AT 250 WORDS)
我们研究了在IgE介导的嗜碱性粒细胞激活后蛋白激酶C（PKC）的变化。用0.1微克/毫升抗IgE处理后，细胞总PKC增加（为对照的169±23%，组胺释放（HR）=33±7%，n = 12），这完全是由于膜相关PKC的增加所致。这些变化在刺激后1.0分钟达到最大值（280±48%），5.0分钟后降至190±38%，不过组胺释放在5至10分钟后才完全完成。我们发现膜相关PKC的增加与组胺的最终释放之间有良好的相关性（rs = 0.902）。嗜碱性粒细胞组胺总释放量低于5%的供体（n = 3，HR = 3±1%）显示PKC有部分激活（173±18%），但远低于其余供体（PKC增加=346±59%，n = 9，HR = 43±7%）。在接触抗IgE后的任何时候，我们都未观察到胞质PKC的重新分布。相比之下，0.1微克/毫升的2-O-十四烷酰佛波醇-13-乙酸酯（HR = 36±3%，n = 3）促进了细胞总PKC的增加、31±4%的胞质PKC的丢失以及膜相关PKC的816±183%的增加。抗IgE对PKC的激活仅部分依赖于细胞外钙。在无钙的情况下，PKC的增加约为1毫摩尔钙存在时的65%（n = 4），但这些水平在更长时间内持续存在，30分钟后未恢复到基线。高于正常浓度的钙（5至10毫摩尔）促进了PKC活性的快速增加并加速了恢复到基线（5分钟后回到刺激前水平）。次优浓度的抗IgE（0.01微克/毫升）减弱了膜相关PKC的变化并改变了反应动力学。达到最大活性所需的时间从1.0分钟增加到5.0分钟，组胺释放速率相应降低。更高浓度的抗IgE（1.0微克/毫升）促进了PKC的快速增加（PKC最大增加=501±59%，时间=0.5分钟，HR = 28±2%），随后同样快速地恢复到基线水平。（摘要截短于250字）
