Tamura N, Agrawal D K, Townley R G
Allergic Disease Center, Creighton University School of Medicine, Omaha, NE 68178.
J Immunol. 1988 Dec 15;141(12):4291-7.
We studied the role of naturally occurring eosinophil chemotactic factors on leukotriene (LT)C4 production from highly purified (87.1 +/- 2.4%) normodense eosinophils. Platelet activating factor (PAF) directly induced LTC4 production from eosinophils in a dose (10(-9) to 10(-5) M) and a time-dependent manner. PAF (10(-5) M) induced 0.74 +/- 0.08 ng of LTC4 production/10(6) eosinophils. However, lyso-PAF, eosinophil chemotactic factor of anaphylaxis, and LTB4 failed to induce LTC4 production within the tested range. Furthermore, the pre-incubation of eosinophils with 5 micrograms/ml of cytochalasin B did not alter the chemotactic factor-induced LTC4 production. When eosinophils were stimulated by the submaximal concentration (1 microgram/ml) of calcium ionophore A23187, the pre-incubation of eosinophils with 10(-6) M or 10(-5) M of PAF, or 10(-5) M of eosinophil chemotactic factor of anaphylaxis significantly enhanced LTC4 production up to 163.9 +/- 17.5% (p less than 0.05), 279.2 +/- 32.9% (p less than 0.01) and 165.2 +/- 21.2% (p less than 0.05) of the control, respectively. However, the pre-incubation with lyso-PAF or LTB4 failed to enhance A23187-induced LTC4 production. The pre-incubation of eosinophils with phosphatidyl serine also failed to enhance A23187-induced LTC4 production. However, the direct stimulation of protein kinase C by PMA enhanced the submaximal concentration of A23187-induced LTC4 production from eosinophils up to 179.5 +/- 20.9% (p less than 0.05) of the control. Our findings indicate that PAF and ECF-A work not only as chemotactic factors but also induce a functionally active state of eosinophils probably through their post-receptor mechanisms, and contribute to the inflammatory processes.
我们研究了天然存在的嗜酸性粒细胞趋化因子对高度纯化（87.1±2.4%）的正常密度嗜酸性粒细胞白三烯（LT）C4生成的作用。血小板活化因子（PAF）以剂量（10⁻⁹至10⁻⁵M）和时间依赖性方式直接诱导嗜酸性粒细胞生成LTC4。PAF（10⁻⁵M）诱导每10⁶个嗜酸性粒细胞生成0.74±0.08 ng的LTC4。然而，溶血PAF、过敏反应嗜酸性粒细胞趋化因子和LTB4在测试范围内未能诱导LTC4生成。此外，用5微克/毫升的细胞松弛素B预孵育嗜酸性粒细胞并未改变趋化因子诱导的LTC4生成。当嗜酸性粒细胞受到亚最大浓度（1微克/毫升）的钙离子载体A23187刺激时，用10⁻⁶M或10⁻⁵M的PAF或10⁻⁵M的过敏反应嗜酸性粒细胞趋化因子预孵育嗜酸性粒细胞可使LTC4生成显著增强，分别达到对照的163.9±17.5%（p<0.05）、279.2±32.9%（p<0.01）和165.2±21.2%（p<0.05）。然而，用溶血PAF或LTB4预孵育未能增强A23187诱导的LTC4生成。用磷脂酰丝氨酸预孵育嗜酸性粒细胞也未能增强A23187诱导的LTC4生成。然而，佛波酯对蛋白激酶C的直接刺激可使亚最大浓度的A23187诱导的嗜酸性粒细胞LTC4生成增强至对照的179.5±20.9%（p<0.05）。我们的研究结果表明，PAF和ECF-A不仅作为趋化因子起作用，而且可能通过其受体后机制诱导嗜酸性粒细胞的功能活性状态，并参与炎症过程。
