Yukawa T, Kroegel C, Evans P, Fukuda T, Chung K F, Barnes P J
Department of Thoracic Medicine, Brompton Hospital, London, U.K.
Immunology. 1989 Sep;68(1):140-3.
We have examined the induction of hypodense eosinophils by platelet-activating factor (PAF), a mediator which may be involved in eosinophil activation in allergic diseases. Guinea-pig eosinophils were incubated with buffer or PAF and applied to continuous Percoll density gradients. Cellular density ranged from 1.0142 to 1.1369 g/ml. Peak eosinophil density in control was 1.0887 +/- 0.0008 g/ml (mean +/- SEM), and 91.1 +/- 1.4% of eosinophils were distributed between 1.0810 and 1.1000 g/ml. Preincubation of eosinophils with PAF(10(-7) M) resulted in a time-dependent and non-cytolytic increase of the number of hypodense eosinophils, with peak densities after incubation for 1 hr and 2 hr of 1.0834 +/- 0.0014 (n = 4, P less than 0.05) and 1.0755 +/- 0.0007 g/ml (n = 6, P less than 0.01), respectively. After incubation for 2 hr, 82.0 +/- 4.9% (n = 6) eosinophils showed a density lower than 1.080 g/ml. Lyso-PAF, the inactive precursor and metabolite of PAF, at a concentration of 10(-7) M had no effect on cell density. The specific PAF receptor antagonist WEB 2086 (10(-6) M) inhibited the PAF-induced density shift by 87.0 +/- 5.3%. Our results demonstrate that a single mediator is able to induce the formation of hypodense eosinophils. We conclude that the appearance of hypodense eosinophils in allergic diseases such as asthma may occur, at least in part, in response to inflammatory mediators which activate these cells.
我们研究了血小板活化因子（PAF）对低密度嗜酸性粒细胞的诱导作用，PAF是一种可能参与过敏性疾病中嗜酸性粒细胞活化的介质。将豚鼠嗜酸性粒细胞与缓冲液或PAF一起孵育，然后应用于连续的Percoll密度梯度。细胞密度范围为1.0142至1.1369 g/ml。对照组嗜酸性粒细胞的峰值密度为1.0887±0.0008 g/ml（平均值±标准误），91.1±1.4%的嗜酸性粒细胞分布在1.0810至1.1000 g/ml之间。嗜酸性粒细胞与PAF（10⁻⁷ M）预孵育导致低密度嗜酸性粒细胞数量呈时间依赖性且非细胞溶解性增加，孵育1小时和2小时后的峰值密度分别为1.0834±0.0014（n = 4，P<0.05）和1.0755±0.0007 g/ml（n = 6，P<0.01）。孵育2小时后，82.0±4.9%（n = 6）的嗜酸性粒细胞密度低于1.080 g/ml。PAF的无活性前体和代谢产物溶血PAF，浓度为10⁻⁷ M时对细胞密度无影响。特异性PAF受体拮抗剂WEB 2086（10⁻⁶ M）可使PAF诱导的密度变化降低87.0±5.3%。我们的结果表明，单一介质能够诱导低密度嗜酸性粒细胞的形成。我们得出结论，在哮喘等过敏性疾病中出现的低密度嗜酸性粒细胞，至少部分可能是对激活这些细胞的炎症介质的反应。
