Raible D G, Schulman E S, DiMuzio J, Cardillo R, Post T J
Division of Allergy, Critical Care and Pulmonary Medicine, Hahnemann University School of Medicine, Philadelphia, PA 19102.
J Immunol. 1992 Jun 1;148(11):3536-42.
Airway damage secondary to eosinophil activation is thought to contribute to the development of asthma. Using the fluorescent dye FURA-2 to measure the concentration of cytosolic calcium, we found that supernatants from anti-IgE-stimulated human lung mast cells increased cytosolic calcium in human eosinophils. We then examined the major mast cell mediators (histamine, PGD2, platelet-activating factor (PAF), eosinophil chemotactic factor of anaphylaxis (ECF-A), leukotriene (LT)C4 and LTB4) for their ability to increase cytosolic calcium in eosinophils. We found that both PAF (5 x 10(-9) to 5 x 10(-6) M) and PGD2 (two of five donors responsive at 1 x 10(-9) M) were potent stimuli for calcium mobilization. LTB4 (10(-8), 10(-7) M) and histamine were also active, although higher concentrations of histamine were required to see a response (3 x 10(-7) to 10(-5) M). LTC4, val-ECF-A, and ala-ECF-A were inactive. The effects of PGD2 and histamine were specific for eosinophils, although LTB4 and PAF increased calcium in both neutrophils and eosinophils. The histamine-induced increase in intracellular calcium was not blocked by the H1 or H2 antagonists pyrilamine or cimetidine (10(-4) M), respectively; however, the response to 10(-6) M histamine was completely blocked by the specific H3 antagonist thioperamide (10(-6) M). To evaluate the relative contribution of these stimulatory mast cell mediators on the calcium mobilizing activity in supernatants from anti-IgE-stimulated human lung mast cell (HLMC), we examined the effect of supernatants from HLMC pretreated with indomethacin and/or the 5-lipoxygenase pathway inhibitor MK886. These supernatants were added to FURA-2-loaded eosinophils that had been preincubated with thioperamide and/or the PAF antagonist WEB-2086. We found that the increase in eosinophil calcium in response to supernatants from anti-IgE-stimulated-HLMC was totally inhibited only when the mast cells were challenged in the presence of indomethacin and MK886, and the eosinophils were preincubated with thioperamide. WEB-2086 had little effect. When we examined the effect of these mediators on eosinophil secretory function, we found that PGD2 (not histamine) primed eosinophils for enhanced release of LTC4 in response to the calcium ionophore A23187. We conclude that the activation of eosinophils by PGD2 and other mast cell products may contribute to airways inflammation that is characteristic of asthma.
嗜酸性粒细胞活化继发的气道损伤被认为是哮喘发病的原因之一。我们使用荧光染料FURA-2测量胞质钙浓度，发现抗IgE刺激的人肺肥大细胞的上清液可增加人嗜酸性粒细胞的胞质钙浓度。然后，我们检测了主要的肥大细胞介质（组胺、前列腺素D2、血小板活化因子（PAF）、过敏反应嗜酸性粒细胞趋化因子（ECF-A）、白三烯（LT）C4和LTB4）增加嗜酸性粒细胞胞质钙的能力。我们发现，PAF（5×10⁻⁹至5×10⁻⁶M）和前列腺素D2（五名供体中有两名在1×10⁻⁹M时有反应）都是钙动员的有效刺激物。LTB4（10⁻⁸、10⁻⁷M）和组胺也有活性，尽管需要更高浓度的组胺才能看到反应（3×10⁻⁷至10⁻⁵M）。LTC4、缬氨酸-ECF-A和丙氨酸-ECF-A无活性。前列腺素D2和组胺的作用对嗜酸性粒细胞具有特异性，尽管LTB4和PAF可增加中性粒细胞和嗜酸性粒细胞中的钙。组胺诱导的细胞内钙增加分别未被H1或H2拮抗剂吡苄明或西咪替丁（10⁻⁴M）阻断；然而，对10⁻⁶M组胺的反应被特异性H3拮抗剂硫代哌酰胺（10⁻⁶M）完全阻断。为了评估这些刺激性肥大细胞介质对抗IgE刺激的人肺肥大细胞（HLMC）上清液中钙动员活性的相对贡献，我们检测了用吲哚美辛和/或5-脂氧合酶途径抑制剂MK886预处理的HLMC上清液的作用。将这些上清液加入预先用硫代哌酰胺和/或PAF拮抗剂WEB-2086预孵育的负载FURA-2的嗜酸性粒细胞中。我们发现，仅当肥大细胞在吲哚美辛和MK886存在下受到刺激，且嗜酸性粒细胞预先用硫代哌酰胺预孵育时，抗IgE刺激的HLMC上清液引起的嗜酸性粒细胞钙增加才被完全抑制。WEB-2086作用很小。当我们检测这些介质对嗜酸性粒细胞分泌功能的影响时，我们发现前列腺素D2（而非组胺）使嗜酸性粒细胞对钙离子载体A23187刺激的LTC4释放增强。我们得出结论，前列腺素D2和其他肥大细胞产物对嗜酸性粒细胞的激活可能导致哮喘特有的气道炎症。
